Yes, the effect is there with the devices turned off.
So, occlusion won’t really go away. If it is minor, you may get used to it and stop noticing it so much. But in my experience, it won’t ‘adapt’ the same way your ears will adapt to hearing high pitched sounds that they have been missing.
Many people are able to happily live with a bit of occlusion effect, especially if it is a trade off for other amplification benefits. But in my experience, even after years of living with occlusion, people will report improved sound quality if they shift to a device that doesn’t have it (whereas once they are adapted to adequate amplification, they generally report decreased sound quality if shifted to a device with less). There is some evidence that this is the case in pediatrics as well. Because children’s ears are so small they basically cannot have any venting when they are little and so for those who have mild loss in the low frequencies they grow up with occlusion, but still report improved voice quality when they can finally be vented years later. (I know I go back to pediatrics a lot, but in some ways it’s a more “pure” data set because these kids don’t have preconceived ideas about how things should sound.)
So you need to ask yourself whether it is mild enough to live with, and more desireable
compared to other options (potentially moving to a behind the ear device, venting a bit more if physically possible but maybe losing some high frequency gain if feedback control is lost*).
But it can also sometimes be tricky to know if it really is occlusion. After a certain degree of low frequency hearing loss, occlusion usually isn’t a problem. Except that biologiy varies, so sometimes it still is a problem. But you need to separate it out from two other issues: 1) adapting to increased low frequency gain (which is why turning the hearing aids off is a quick and dirty trick) and 2) the sensation that your ears are ‘plugged’ with the hearing aids in (which will remain even when the hearing aids are off because your ears ARE plugged, but can be resolved with more amplification–essentially restoring the little bit of sound that is being blocked by having something in your ears).
Crunching, booming footsteps, your own voice echoing in your ears when the devices are in and off, tend to be the strongest issues with irritating occlusion.
*One is allowed to make decisions that negatively impact their hearing in order to improve their comfort/convenience/preference, as much as audiologists may resist it. 
You’re ignoring this member’s posts.
