What is a communication breakdown caused by two cultures/societies trying to adapt one another's mores called?
You could dub such a breakdown as symptomatic of the Alphonse-Gaston syndrome:
a pair of persons exhibiting an excessive usu. exaggerated politeness or deference to each other esp. about not taking precedence
Origin:
after Alphonse and Gaston, characters displaying excessive politeness and often uttering the phrases “after you, my dear Gaston” and “after you, my dear Alphonse” that appeared in the comic strip Alphonse and Gaston by Frederick B. Opper †1937 Amer. illustrator and cartoonist
Wikipedia expounds thusly:
The strip faded from public view shortly after Opper's death in 1937, but the catchphrase "After you, my dear Alphonse" lived on. It continues to the present day, spoken in situations when a person receives a dare to do something difficult or dangerous or both; the catchphrase returns the dare to the person who made it. Sometimes it is said when two people are simultaneously trying to go through the same doorway and awkwardly stop to let the other go through.
Alphonse and Gaston exchanges have also been employed by sportscasters during baseball broadcasts when two outfielders go after the ball and it falls in for a base hit. Shirley Jackson used the phrase as the title of her short story, "After You, My Dear Alphonse," published in the January 16, 1943 issue of The New Yorker.
The phrase "Alphonse-and-Gaston routine", or "Alphonse-Gaston Syndrome", indicates a situation wherein one party refuses to act until another party acts first. From a September 23, 2009, New York Times editorial: "For years, China and the United States have engaged in a dangerous Alphonse-and-Gaston routine, using each other’s inaction to shirk their responsibility."
I also ran into a loosely related term named xenocentrism:
oriented toward or preferring a culture other than one's own
This is really just a case of adapting behaviors in order to follow local customs and "fit in".
So "fitting in" might be an apt term.
There is also an idiom "When in Rome, do as the Romans do" that suits your examples and so "doing as the Romans do" might be used as a verb phrase.
You may also hear people responding to question about why they are doing something they don't normally do when visiting a foreign place with, "You know, 'When in Rome...' "
The term is culture clash.
a conflict arising from the interaction of people with different cultural values
See also
When one or more cultures are integrated into one environment, causing disruption and challenging contemporary traditions. Often occurs in multicultural societies.
Being ‘too accommodating’.
Accommodating the other so much that the opposite of what you want to happen (eg, social connection, ease) happens (eg, dis-ease, frustration...)
‘Bending over backwards’ ‘to accommodate someone’.
So you arrive - back at the start of the circle.
https://www.vocabulary.com/dictionary/accommodating