If you are an Apple Music user in its individual mode, you will not be able to listen to music on your HomePod and on the iPhone at the same time. This is something that Apple collects in the terms of service, and that therefore we knew could happen at any time, but until now the company turned a blind eye and therefore many took advantage of it.
The reasons for this change? We do not know them because the company has not communicated anything about it, it has not made any announcement of this change, it simply has happened and this is how many users are telling it on Reddit. Are you one of those affected? The only solution is to create a family account.
Apple Music has two main modalities: individual accounts for € 9,99 per month and family accounts for € 14,99 per month. If you are a student, you also have the possibility of getting a special subscription for € 4,99 per month. The Apple Music terms of service are very clear: individual accounts can only be played on one device at a timeWhile family accounts can do it on up to six devices at the same time. HomePod counts as one device, so if you're playing music and you have an individual account, starting to play music on your iPhone will stop HomePod.
This is something that already happens in other services like Spotify, and as we say Apple includes in its conditions, but surely it will raise many blisters among users who until now were taking advantage of this "flexibility" that until now Apple was having. The reasons for the change? From what they say on Reddit, Apple told a user that it should always have been this way, but that due to a bug (which they have now fixed) the HomePod did not count as an additional device. What if I have two HomePods in different rooms? Well, the same thing will happen.