I can confirm this same behavior. However, it only happens in some reports and not others. I believe it may be related to custom visuals. In the past, I reported another issue where the "rendered" method was firing before custom visuals were rendered that I don't believe was ever fixed. Again, this used to work and was broke. If PBI Embedded is ever going to a great solution they need to do a better job of locking the service down when something is working instead of allowing new bugs to be introduced to support new features that are not needed for our use case. It is difficult to tell our customers that things are broke because MSFT introduced a bug when the whole point of PBI Embedded is that we can brand it and sell it as our own.
At a minimum, we need to be made aware of what and when something changes in the backend. We had a rude awakening to discover this week some odd behaviors that we were certain did not exist before. Like you, we have customers that are using these embedded reports and we would have to explain to them what's going on.
@Bjarkiek, I don't have a good update for you. @hawdong pointed out that it does successfully fire on subsequent pages. So I coded a temporary workaround to just sleep a sufficient time on the first page to get us by for now. We weren't able to identify why some reports work and others do not. There must be some common thread, but not sure what it is at this point. This is the third "temporary workaround" I've had to implement due to breaking changes with PBI Embedded, so I am getting quite frustrated with the product unfortunately. FYI, I upgraded to the latest powerbi.js file (2.7.1), and it had no effect.