iPad no longer locks upon closing magnetic lid of case. Lock/unlock is on.

I have noticed that recently my iPad no longer locks when I close the lid to its case. I have had this same case, just in different colors, for the entire time I’ve owned this iPad. It is an iPad Pro 12.9” 5th Gen and is on iOS 17.3. The lock/unlock feature is on, but doesn’t work. I have tried everything listed here in this thread by someone earlier this year with the same problem, IPadOS 16.5 cover Lock / Unlock not worki… - Apple Community

but nothing has changed, it still doesn’t work. The magnetic part is sticking when I close it, I’ve tested this and have made sure.