Reviving this thread as I found a viable solution. After have the same issues other did with the locks sticking, or the back brace popping off and not able to open the latch I spoke to someone at Locks and More who is the supplier for Miramar and Challenger basement locks.
Seems there was an issue with the size of the crossbar and thread holes on the four corners for the locks made in 2015 - 2017. No warranty by the manufacture unless you notified Thor in the first year. But the issue was resolved. So I ordered a new one and it worked great. So then I called them back, explained my situation and asked what we could do if I bought the whole set, they gave me a good discount. Replaced all of them with a new keycode that is not the one the dealer users. All doors locks are nice and tight now without sticking latches or the cross bar slipping and preventing opening up the compartment.
Here is the one that seems to have been used on Thor Miramar and Challengers for a few years, it's called the southco
https://www.rvlocksandmore.com/Locking-Slam-Latch If you call them you can get them all keyed the same.
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