Despite being visibly transparent to both players and endermen, endermen will not be aggravated when stared through glass.
MC-169391
Endermen cannot be angered when stared through glass
Resolved
Duplicate
1
muzikbike
(Unassigned)
Confirmed
(Unassigned)
1.15.1
Retrieved
The wiki says Endermen cannot be provoked by players looking at them through transparent blocks.
Probably intentional.