Hans has made a patch that I have commited on Sun 23 Jan 2022, r7484 New primitive \matheqdirmode. By default the short skip detection is not adapted to r2l typesetting and that hasn't been the case since the start of the project. Changing it could break hacks that users came up with but when you set \matheqdirmode to a positive value direction will be taken into account.
Great. Thank you. Javier
