The uploaded file likely exceeded the maximum file size (32 MB) that this server supports on remove image In my taxonomy terms,when I try to edit a term I got this error : 


  An unrecoverable error occurred. The uploaded file likely exceeded the
  maximum file size (32 MB) that this server supports.


even though I didn't try to upload a file,I tried to remove the uploaded file.
and I don't have mod_security module enable on my server .( as I search through google,there was problem with mod_security apache module and ajax).

I have no idea why this is happening only on particular vocab terms,not in anywhere else.
For sure this is due to some problem with your sever setting, contact your webhosting company and talk with them regarding the issue.

It could be due to ModSecurity which is an  is an open sourceweb application firewall Apache module. which help in providing an external security layer that increases security, and help in preventing attacks.

The other reason could be the size your allow to upload that can be change in your server setting. It is also important to check apache max_execution_time.

If you have control over your server then you can try to change your php file 

post_max_size = 128 MB
upload_max_filesize = 32MB