There is no setting I know of in Gimp preferences. Difficult to say when a MacOS is involved.
I sometimes have a similar problem, often cured by re-selecting the entry in the linux clipboard manager. Sometimes fixed by pasting into a pure text editor to remove any formatting. Then select from that and paste into Gimp.
First thing to try is some text in a pure text editor and a copy/paste into Gimp. Maybe I am lucky, my linux text editor kwrite also has a spell check.
I sometimes have a similar problem, often cured by re-selecting the entry in the linux clipboard manager. Sometimes fixed by pasting into a pure text editor to remove any formatting. Then select from that and paste into Gimp.
First thing to try is some text in a pure text editor and a copy/paste into Gimp. Maybe I am lucky, my linux text editor kwrite also has a spell check.