I've never had a slave glitch. However, in order to complete training, a slave needs 0 pride (top stat of the bottom set of stats during training, even 0.1% wont be tamed) and I believe a sum of 150% of lust, affection, and tameness (next 3 stats). So if she has 0% pride and 50% lust, 50% affection, and 50% tameness she'll complete her training, for example.
In Cheat Engine, change the Value Type from 4 Bytes to Double. I personally use the Truncated option of the 3 they give to scan Double values, then search for the first 2 numbers of the stat you're looking for since the last one is rounded in this game, and it may not show up if you search for the exact value shown.
As an example, if you're looking for a Lust of 43.7%, search for 0.43 then go back into the game, do something to raise lust to at least 44.1% and then search for 0.44 in Cheat Engine and it should be the only remaining value.
Note that single-digit stats, like 7.3% affection should be searched for as 0.07 and 100% or higher are 1.00 or higher when searching for them.
When editing stats, all stats have a min of 0 and max of 1 except for skill, which has a max of 0.5 + [number of hands the slave has] * 0.5 so if your slave has 2 hands, they have a max skill of 1.5, no hands has a max of 0.5, and 6 hands has a max of 3.5.
Finally, if you choose to do something like freeze your and your slave's stamina for an infinite training session, keep in mind the game sometimes re-allocates memory, so there's a chance that if it re-allocates while a memory location is frozen, it can cause the game to crash. It's possible to freeze stamina for a VERY long time, but make sure you save before trying this to make sure you only lose that training session if the game does crash.