It's just the way it is. Different hosts, different host configurations, different fediverse software, different software configs, and all that.
Few people are aware today but when Google Mail was first beta tested (very early invite days), we did experience a lot of issues. Mails from Y!Mail not arriving. There was also one time when a mail from another server arrives garbled.
Apologies for using the email analogy again.
Let me use the mobile analogy as another example. Here in the Philippines, I don't know in other countries, we've had interoperability issues a decade or two ago. The Philippines is the SMS capital of the world, so imagine our frustration because the two major (and only) SMS providers cannot interoperate reliably.
Two different networks. Two different systems. Trying to federate to each other.
There will indeed be interoperability issues.
They haven't really solved it, but it was at least minimised.
So, yes, we have to accept that it is going to be a long road until we achieve the level wherein these challenges you have mentioned are minimised in the fediverse as well. I'm sure, politics aside, the #ActivityPub developers are finding ways. ^_^