Both 2.1.26 and 2.1.33 are run under the same circumstance, ie ceteris paribus. Same computer, some add ons, same software installed.
ctrl+alt+shft+C works fine one 1.26, upgraded to 1.33, I did not restart the computer or closed any software, went straight into 1.33, within 2 minutes I found ctrl+alt+shft+C not working. The only variable in this situation is the anki software.
If another software is stealing the ctrl+alt+shft+C shortcut, then how come it works in 1.26 but not 1.33?
It could be due to a change in the toolkit Anki uses. Maybe something about key presses handling has changed. I don’t know.
I don’t think this is caused by a direct change in Anki. It seems the last change to the code that handles the cloze shortcut is years ago.
But I recommend checking other software as mentioned in the FAQ link.