[AnAmericanMother]

That's correct. The Catholic Church doesn't have a problem with Orthodox making communion with us, but often the Orthodox authorities do have a problem with that. The guide in the back of our missalette says that Orthodox believers are welcome to commune, but that they had better check with their bishop or metropolitan first.

[rzman21]

Some Oriental Orthodox jurisdictions like the Syriacs and Armenians allow Catholics to take communion. The Ukrainian Orthodox in the US used to, but I don’t know if that’s still the case since their former bishop died.