I have noticed that APU's EGT does raise when bleed air consumers get connected (engine starter valve most prominently):
However, when hooking up electric consumers to the APU generator (or hooking the whole busses to the APU gen), the EGT doesn't flinch:
I have no real aircraft at hand to verify, but from experience with other aircrafts I would have expected to see the EGT react also on electrical load changes. I couldn't find any videos for the real thing where the EGT display is fully visible on generator hook-up (in most videos it's just covered by the pilot's or FO's hand grabbing the APU GEN connector switches...). But again I don't know how it would work exactly in a 733, so probably someone can enlighten me wethere this is the typical behaviour, of if it's still on IXEG's todo list