I have two vans, both with power locks that have the same issue.
The slider door lock on the inside seemed to be spring loaded and would stay unlocked until you lock it.
Are they spring loaded?
They both will stay locked and the knob on the inside is loose, up and down not in the threaded area.
Do you have to replace the entire lock or can you gain access to the spring and R&R?

TIA

dylan