If the hero tinker first uses the ability “pocket factory”, and then uses tome of retraining before “pocket factory” completely cooldown, the “pocket factory” will be the default ability.
The workaround I found is to let “pocket factory” completely cooldown, then use tome of retraining, the tome will work as usual.
This bug is not random, I have encountered this bug more than 10 times.
Please fix this bug.