Object opacity not working in InDesign 18.0

[Alienduck]

I've opened and saved a file from the previous version. A master page item was set to opacity = 25%. Althought the opacity still says 25, it is solid and blocking out other times. I tried reducing the opacity. nothing. I even set it to 0. - No difference. I restarted indesign and the computer itself. - no difference. 

Anyone know what might be causing this? -- it was working fine before, but now.... nothing. 

[Steve Werner]

Does this happen only with this file or with more than one file?

If a single file, there may be corruption. Try saving as IDML (File > Save As > InDesign CS4 or Later {IDML). Reopen the IDML file.

I more than one file, try restoring your InDesign preferences and caches. Here's how:

https://www.rockymountaintraining.com/adobe-indesign-rebuilding-preferences-cache/

[Alienduck · Accepted solution]

Steve,

I should have checked that before posting. I am not sure what was causing it or what "fixed" it, but today there is no issue. I didn't even shutdown last night. -- Thanks for your suggestions anyway. 

[Steve Werner]

I'm glad the problem fixed itself!