Hi,
after update from 1.9.3.7. to 1.9.3.8 the cart URL report this error, but only for registered customer and not for not registered customer (occasional)
https://mysite/checkout/cart/add/uenc/aHR0cHM6Ly9hc3BpcnRlYW0uaXQvYXNwaXJhcG9sdmVyZS1jZW50cmFsaXp6YXRvLWEtbXVyby1lbmtlLWNlMDctaW4tbWV0YWxsby1sdWNpZGF0by5odG1sP19fX1NJRD1V/product/51/form_key/IsFKrabwUbheL04d/
I not able to resolve it. If I restore at 1.9.3.7 all return ok!
Was the problem solved i am facing same
I could no longer solve the problem. I only know that it's not due to the conflict with an extension. I was no longer able to update my platform over 1.9.3.7 and I'm not happy of this.
The embarassing thing is that it only happens with registered users.
It could be due to a conflict with the database but I am not a professional developer but the same problem in two platforms at the same time it's really strange.
I'm facing this same problem, but it won't occurs often
I've find two days ago this old post on the forum:
It's the same problem persist.
When the compiler is disabled and the registered user add produts to cart result a blank with a long url code.
Now he path SUPEE-10570v2 is anymore available and I could not test if inserting the patch solves the problem