Not only is this not normal and totally unreasonable, it is beyond insane.
Take this question, for example: you licensed it to Stack Overflow, Inc. under an irrevocable, perpetual license. Therefore, it is impossible for you to legally sign this contract:
- If you don't transfer ownership of this question to your employer, you violate the Terms of your employment contract.
Whatever you do, you will violate someone's Terms.
Similarly for everything you created for any of your previous employers. You cannot legally transfer ownership of that IP to your new employer. Only your old employer can do that. So, you have to go to every single one of your former employers, and ask them to transfer ownership of every product you worked on to your new employer.
Say you did an internship at Microsoft after school and fixed some bug in Explorer? Congratulations, your new employer is now the proud owner of Windows, and Microsoft is no longer allowed to sell it!
That is just ridiculous.