The following blocks/entities cannot be placed on top or on the side of froglights:
Signs
Banners
Cakes
Paintings
Item frames
Other full-block light sources don't have this issue.
MC-249265
Some blocks cannot be placed on froglights
Resolved
Fixed
10
Also affects banners and cakes (MC-249278) as well as item frames and paintings (akin to MC-213841). Added all of these to the bug report as well.