Every time I use "Call Dragon" shout Odahviing never comes when I'm on Solstheim. He still comes and helps out on mainland Skyrim, just never on the island.

I dont think he is 'supposed' to.

Yeah, I tried too, lol. No show. Guess it's too far away, even for the Dragonborn.

Hes Afraid of Miraak
He doesnt want Soul svck.

I noticed this also when playing yesterday. It's probably another bug unless the developers can confirm that it was done on purpose.