There have been a bunch of discussions about handling a "Year" value in a file name during import. But MC, and its file naming reading function called CARNAC, should have handled those file names correctly. I suspect that something went wrong with your initial import, hence the earlier issue, and now this one.
If the initial import was really mucked up then clearing the Library and re-importing may be the best solution. But if there are just a few little problems like this then it would be best to fix them.
Now, the latest change that impacts this was;
25.0.74 (7/8/2019)
1. Changed: When doing a movie lookup, the year will be stripped from the name if the movie is named like [Name] ([Year]).
That means that a metadata lookup using the "Get Movie & TV Info..." function should fix the problem you are seeing. So;
Backup your Library using the MC backup function.
Select a few of the problem movies in MC.
Right-click on one of the movies and select "Get Movie & TV Info...".
Did that fix the movie name, as shown in the [Name] field?
I just did a quick test of that with a couple of movies for which I altered the name to match the problem you have. It fixed the problem on both. Note that you need to tick the box "Allow overwrite of existing values".
Test on a small number of files initially. If it doesn't work for them you can just use Ctrl-Z to undo one run of the tag changes that "Get Movie & TV Info..." does.
If the test was fine, then run "Get Movie & TV Info..." on larger lots of movies. If it all looks good, run it on the remaining problem movies. Note that the lookup can take some time for lots of movies.
If trying this all goes wrong, you can Restore the Library backup you made earlier.
Note that if the above lookups are just taking too long, and the movie name is the only thing wrong with the metadata, then there is another easy way to fix the name.
Select the movies that have the problem name.
Edit the [Name] field using F2 or right-click and select "Rename".
Enter this expression into the [Name] field;
=removeright([Name], 6)
That will remove the right six characters in the name, " (yyyy", and leave the correct name intact.
You may want to consider this second method rather than do the lookups, as it will be fast. Just make sure that you backup your Library first.