You are correct that the Emphasis control for the OptTronik gets reset in V1.90 due to changes in its behaviour. There is a warning to this effect at the top of the Release Notes but it wrongly mentions Libraries only. In addition to the variable Emphasis as it existed in V1.8, we added two fixed modes with an 80Hz HPF and an 80Hz-5kHz band pass. These of course operate on the sidechain, not on the compressor output.
Two other models had minor changes. The Opto compressor has some improvements to the Transient and Burn behaviour (but there is no ‘reset’ of settings in this case and the differences are very subtle), and the de-esser now has three filter types.