not sure why, but i am able to save the settings of the offset and centered text in both the default setting & the favourites.
when you eyedrop an already placed dimension with the offset setting, don't eyedrop from the dimension lines. eyedrop from the text box itself. with this as the default, the next time you place a dimension with custom text, you'll now see the that it inherits the text box alignment.
i didn't have a problem saving both a centered & offset text alignment as favourites.
i just did a comparison with 2 favourites -- one with a normal centered-text dimension fav & the other i created off an already created offset-text dimension. i placed the dimensions in the model & put some text & they align in whatever the favourite was set to.
try eyedropping the text box instead of the dimension line itself. also, you'll definitely need to do this in the template file, otherwise, any future AC files created with this unwanted text box alignment, will continue to have this because it was the original setting in the template.
check your notifications. i believe the email notifications are opt-in by default. you always will get emails (replies to the thread, replies to one specific comment, likes received on a comment...etc)