Error with schema validation using dev mode

[SimplyComplexable]

I'm getting the following error when I try to use the dev mode version of the tracking plan

Error: strict mode: unknown keyword: "isNewProperty"
    at checkStrictMode (util.js:174:15)
    at checkUnknownRules (util.js:32:13)
    at alwaysValidSchema (util.js:19:5)
    at Object.code (items.js:17:42)
    at keywordCode (index.js:464:13)
    at eval (index.js:222:17)
    at CodeGen.code (index.js:439:13)
    at CodeGen.block (index.js:568:18)
    at iterateKeywords (index.js:219:9)
    at groupKeywords (index.js:200:13)
    at eval (index.js:192:13)
    at CodeGen.code (index.js:439:13)
    at CodeGen.block (index.js:568:18)
    at schemaKeywords (index.js:190:9)
    at typeAndKeywords (index.js:128:5)
    at subSchemaObjCode (index.js:115:5)
    at subschemaCode (index.js:91:13)
    at KeywordCxt.subschema (index.js:438:9)
    at applyPropertySchema (properties.js:45:17)
    at Object.code (properties.js:33:17)
    at keywordCode (index.js:464:13)
    at eval (index.js:222:17)
    at CodeGen.code (index.js:439:13)
    at CodeGen.block (index.js:568:18)
    at iterateKeywords (index.js:219:9)
    at groupKeywords (index.js:200:13)
    at eval (index.js:192:13)
    at CodeGen.code (index.js:439:13)
    at CodeGen.block (index.js:568:18)
    at schemaKeywords (index.js:190:9)
    at typeAndKeywords (index.js:128:5)
    at eval (index.js:70:9)
    at CodeGen.code (index.js:439:13)
    at eval (index.js:37:166)
    at CodeGen.code (index.js:439:13)
    at CodeGen.func (index.js:587:18)
    at validateFunction (index.js:37:13)
    at topSchemaObjCode (index.js:62:5)
    at validateFunctionCode (index.js:21:13)
    at Ajv.compileSchema (index.js:80:45)
    at Ajv._compileSchemaEnv (core.js:473:37)
    at Ajv.compile (core.js:160:38)
    at Ajv.validate (core.js:151:22)
    at validateAgainstSchema (segment.ts:1677:14)
   (... project files)

I can see this isNewProperty field in the schema generated and validated against in the segment.ts file, but obviously I can't change this as it's generated.

{"$id":"Product_Added","$schema":"http://json-schema.org/draft-07/schema#","description":"Fires when a user adds an item to their cart","properties":{"affiliation":{"$id":"/properties/affiliation","description":"","type":"string"},"basket_token":{"$id":"/properties/basket_token","description":"","type":"string"},"brand":{"$id":"/properties/brand","description":"","type":"string"},"cart_id":{"$id":"/properties/cart_id","description":"","type":"string"},"category":{"$id":"/properties/category","description":"","type":"string"},"coupon_name":{"$id":"/properties/coupon_name","description":"","type":["array","null"]},"currency":{"$id":"/properties/currency","description":"","type":"string"},"description":{"$id":"/properties/description","description":"","type":"string"},"essential_products":{"$id":"/properties/essential_products","description":"","type":["array","null"]},"image_url":{"$id":"/properties/image_url","description":"","type":"string"},"list_name":{"$id":"/properties/list_name","description":"","type":"string"},"name":{"$id":"/properties/name","description":"","type":"string"},"price":{"$id":"/properties/price","description":"","type":"number"},"product_id":{"$id":"/properties/product_id","description":"","type":"string"},"products":{"$id":"/properties/products","description":"","items":{"$id":"/properties/properties/properties/products/items","description":"","isNewProperty":true,"properties":{"category":{"$id":"/properties/properties/properties/products/items/properties/category","description":"","type":"string"},"description":{"$id":"/properties/properties/properties/products/items/properties/description","description":"","type":"string"},"discount":{"$id":"/properties/properties/properties/products/items/properties/discount","description":"","type":"number"},"image_url":{"$id":"/properties/properties/properties/products/items/properties/image_url","description":"","type":"string"},"name":{"$id":"/properties/properties/properties/products/items/properties/name","description":"","type":"string"},"position":{"$id":"/properties/properties/properties/products/items/properties/position","description":"","type":"number"},"price":{"$id":"/properties/properties/properties/products/items/properties/price","description":"","type":"number"},"product_id":{"$id":"/properties/properties/properties/products/items/properties/product_id","description":"","type":"string"},"quantity":{"$id":"/properties/properties/properties/products/items/properties/quantity","description":"","type":"number"},"sku":{"$id":"/properties/properties/properties/products/items/properties/sku","description":"","type":"string"},"url":{"$id":"/properties/properties/properties/products/items/properties/url","description":"","type":"string"},"variant":{"$id":"/properties/properties/properties/products/items/properties/variant","description":"","type":"string"}},"required":[],"type":"object"},"type":"array"},"quantity":{"$id":"/properties/quantity","description":"","type":"number"},"sku":{"$id":"/properties/sku","description":"","type":"string"},"url":{"$id":"/properties/url","description":"","type":"string"},"variant":{"$id":"/properties/variant","description":"","type":"string"}},"required":["brand","affiliation"],"type":"object"}

It seems similar to this issue resolved with this PR. So I think these properties just need to be stripped before writing the file, but not certain.

Thanks for looking into this!