Problem with the IDE: "ctags: bad CPU type in executable"

Hi, I'm a Mac user and I recently update to MacOS Big Sur (from Mojave). Now when I try to compile an Arduino sketch, I encounter this problem:
fork/exec /Users/Mattia/Library/Arduino15/packages/builtin/tools/ctags/5.8-arduino11/ctags: bad CPU type in executable
I tried to get some help online, and it seems a problem related to MacOS refusing to use any 32-bit software, but I'm using the latest version availale already (1.8.15). Also, after 3/4 times I press the compile button consecutively, it compiles the sketch without any problem (and then starts again with the error). I've tryed also the cli tool, but I get the same problem.
Any suggestion on how to resolve my problem?
Thanks!

I see another report of the same here:

Please try deleting the /Users/Mattia/Library/Arduino15/packages/builtin/tools/ctags/5.8-arduino11 folder and then compiling some sketch again. Does the problem still occur after that?

Wow, now seems working. Thanks!
Can I ask why the removal of that folder resolved the problem? Arduino now looks at a new compile tool that run on 64-bit?
Thanks again!