Entirely possible, as app updates/compatibility layer updates are often necessary/happen post-OS update - there was a compatibility layer update for P+ (as with most apps), but not an app update (and still no 4K/HDR playback).
Everyone should go to Twitter and send a tweet to @thomasryan, the CEO of Paramount+ and ask him when this will get resolved and what he plans to do to compensate his customers, since we can't seem to get a straight answer from Paramount+ customer service or their so-called "tech team."
I recall that being the process to get Netflix ATMOS support on my TCL Roku TV's after years of waiting and eventually giving up hope. Roku OS 10 update was delivered to TCL Roku TV's and then shortly behind it was a Netflix app update and 'BAM' ... ATMOS passthrough support. Let's hope that is the path here. If we have to 'wait' for another major Roku OS update to 'maybe' get a fix, that will likely be a lengthy wait.
BenQ HT2060 4LED Projector | ONN 5.1.2 Dolby ATMOS Soundbar | FTV4K MAX TCL Roku-TV 55P605 (4K/HDR/DV) | VIZIO SB36512‑F6 ATMOS Soundbar | FTV4K MAX TCL Roku-TV 43S425 (4K HDR) | FTV4K MAX TCL Roku-TV 32S301 (720p) | FTV4K MAX
Paramount+ has been without HDR since December 2021, and just a few weeks ago, HBO Max lost the ability to play Dolby Vision. @RokuDanny-R indicated that Roku OS v11.0 would fix the issue with Paramount+. For those who have received the v11.0.0 update, we know that is NOT the case, as HDR is STILL not working on Paramount+.
As for P+: If you carefully parse @RokuDanny-R's statement about this you will notice he doesnt explicitly state that OS11 would fix the issue:
"We believe we have found a resolution for this issue and expect this to be resolved once OS 11.0 has been fully released."
It doesnt state that OS11 will be the resolution, just that they expect it to be resolved once OS11 has been "fully released" (whatever that means, since we dont know Roku's metric for an OS being "fully released").
It could easily be that Roku found an issue with the P+ app/service, communicated this to P+, and who then decided to wait for the "full release" of OS11 (perhaps on Roku's advice to limit support confusion etc).
Or, it could be that the particular functionality/fix in OS11 that the P+ app needs will only be implemented at a certain (unknown to consumers, but known to Roku) OS11 build level and later.
@RokuDanny-R could clear a lot of this up by stating whether the issue is with OS10.5 and/or the P+ app, and what constitutes OS11 being "fully released".
As for HBO Max and loss of 4K/HDR10/DV/etc, that is impacting several platforms for several weeks now, and needs to be addressed to HBOMax