sajha keto bro, does your contract say anything such as if you join vendor/client within certain period of time you will be fined certain amount of $$?
TBH it should not really matter unless your employer has to release you in order for you to be able to accept full time offer.

But bro, reading your query I understood, you are getting paid only 10k less than the client and then your employer is working on your GC process as well, right?

You have good thing in both hands. Just in case if there seems to be a trouble joining the client, dhoti sangai basda ni dherai ghata ta chhaina raichha.