They did the same thing to me, just finished chatting with support, and asked them directly if they were aware of an issue with the lastest firmware, and he said"no issue reported" I even sent him a link to the forums....
I hit the same issue recently in Netflix for my Q70 connected to a Pioneer VSX-822 via HDMI-ARC. I eventually switched to using Optical to the receiver and everything works great thereafter. I read in a few other forums that DD+ over ARC is sketchy at best, especially with older receivers, so will probably stick with tried and true optical for the time being. Hope that helps others struggling with the same issue.
I am having the exact same issue. On the Netflix app (and only the Netflix app) for some reason, the audio format is locked into Dolby Digital Plus and cannot be changed (it is greyed out). This is was never an issue before the latest firmware. My receiver can't handle Dolby Digital Plus over HDMI and I get a terrible buzzing sound as soon as the app opens.
I would use optical, but I haven't been able to figure out how to use ARC and Optical at the same time.
Firmware version 1351.3
Just chatted with Netflix customer service describing my issue and also referring to the community chats here. They told me that the issue has been escalated to their technical team and that they're working on it (but they also cautioned that it might take days or weeks to get resolved). Given I only have the issue with Netflix (all my other apps work fine) it probably needs to be resolved on their side.
I have spoken with both Samsung and Netflix. Both blamed each other. I started with Samsung then went to Netflix. Both via live chat.
Netflix was adament that it was the Samsung TV update and nothing to do with their updates. Then I went back to Samsung who after doing a remote connection told me that my reciever was not compatable. I said this made no sense as it was working a few days ago no issue, but as soon as the 1351 update dropped everything stopped working. I also referenced the numerous other people who had different recievers than me and were complaining.
I also referenced the fact that no other app has this problem except for Netflix. The tech offered me nothing and I told him to at least send this up the chain as this problem isn't going away and is effecting a lot of people who are not happy with Samsung right now. I asked if I could roll back the firmware and he said it was not possible. I have no idea what these guys know.
All I know is that everything was working fine until someone pushed and update and now Netflix is messed. There is no reason to take away audio output options especially since a lot of content is not DD+. It is clearly an error but no one will say, yes thats a problem, we will look into it. They just want to push blame. Unreal.....
As in interim solution - until Samsung and/or Netflix have fixed their software problem - I installed an optical cable between my TV and my Denon in addition to the HDMI ARC connection. It allows me to switch Sound Output to Optical when watching the Netflix app (with Digital Audio Output Format preset to Dolby Digital).
In my case it's not only related to Netflix, yes it's the only app affected, but I can't use my PS4 connected via the receivers HDMI/ARC I have no video nor audio signal, yes I could work around it, but i shouldn't have to, they scheduled a technician for today, we shall see, all I know is that prior to this firmware update everything worked perfect....