A Tower Controller reported two aircraft in a row initiated go arounds due to receiving Terrain Warnings on short final. The reporter reviewed the aircrafts' approach paths and reported they both complied with the appropriate crossing restrictions on the approach.

Narrative

Aircraft X announced to Local Control that they were going around. This was also very surprising as the weather was good for meeting the minimums; and no one else had gone around for quite some time; except the previous arrival Aircraft Y. There was also a consistent crosswind however no wind shear of any kind reported. They were given go around instructions and read them back. They were given go around instructions; read them back; and Local coordinated with TRACON. When the Controller asked the pilot for the reason; they also stated terrain warning. The go around was coordinated with Clearance. There was no Low Altitude alert generated from the surveillance equipment.In this case; there was Aircraft Z that had been waiting for departure to cross XXL and depart XXR. I told the Local Controller to coordinate 3;000 ft. with TRACON with the go arounds at 4;000 ft. and launch them XXL beneath the others; as they were a northeast departure and the go arounds would be turned to a south downwind. This was successfully accomplished; albeit a little hesitantly. Watching the replay; they were not descending at a steeper than normal rate to meet the crossing at ZZZZZ at 1;800 ft. After ZZZZZ; they were descending at a normal rate to the 3.5NM 1;200 ft. crossing with rising terrain beneath them. It is only speculation; but experienced speculation just the same; that their rate of descent triggered the GPWS. Something funky occurred with these two aircraft and only these two aircraft. They were both same aircraft fleet and assumably the same nav/GPWS package. Maybe that needs to be looked at for an update.