Yes, eyelid twitching (myokymia) is a classic sign of magnesium deficiency. Very common complaint in my GLP-1 patients.
I want to emphasize that electrolyte monitoring should be part of routine follow-up for anyone on GLP-1 RAs, especially in the first few months. I check a BMP and magnesium at baseline, 1 month, 3 months, and then every 3-6 months. Too many prescribers write the script and don't do adequate monitoring.
The combination of reduced oral intake + potential GI losses (diarrhea, vomiting) + increased water intake diluting electrolytes = a perfect setup for deficiency.