Welcome to the real world,
sorry you had to find out about it this way.
I cut my teeth on the crap of so called honesty and malarky that was sold at Onsite Trading, only to leave those bastardos and succeed.
You might want to keep better company next time.
Simply put, if you transfer to another location requiring a license, then they will or might be nasty and frustrate the release of your license.
Request your U5 before you leave and do not allow them to send it later, do not allow them to mark it up with derogatory comments or confront them and have them remove them.
Keep your own copies and present your clean copy at the next firm! You can seek redress should this not work cleanly.
Also, seriously consider not going to another location that requires a license. There are more, and you maintain normal customer protections of your monies and rights. Being licensed leaves you in the lurk of employer / employee disputes, where there are no protections of your monetary assets.