Yes, It just magically stopped working.
I found the following in cpanel error logs now:
Deprecated use of DOMAIN as a variable in DOMAIN : ./frontend/x3/trendysitebuilder/index.php at /usr/local/cpanel/Cpanel/ExpVar.pm line 130
Cpanel::ExpVar::expvar('DOMAIN', 0, 1) called at cpanel line 3682
main::doprint('DOMAIN', 0) called at cpanel line 1632
eval {...} called at cpanel line 1632
main::real_exectag('') called at cpanel line 4094
main::dotag_finished_headers(1) called at cpanel line 3914
I think I'll just rerun ucp --force