Checking the code, the addon needs to be modified to read the original pose from evaluated data (e.g. context.depsgraph.id_eval_get()). Most likely, we should just modify get_current_pose() (or the store_bone()) inside it.
The add-on seems to work fine when there is no animation data on the armature object (useless for production, I know). The problem seems to be in the application of a pose on top of an already-animated armature, which is what Sergey is working on now.
Hello Sybren and Hjalti, you say it's fixed by D3448, but so far I've been trying to install it for 3 days, tried to place it in the addons folder direclty, ... with 2.80 and I just get an error: check console. ( I don't manage to open the console like we used to in passed versions ), so if I check the python console, there's no error message. I've been trying other alternatives, Pose Tools addon, and the other version of this addon by Jasper before Sybren adapted it to EEVEE, but nothing seems to work. I checked the video of Pablo and Hjalti but that was before the beta version, and it seemed to work fine. So, could you please point me out to the correct version that works with 2.8, please.