Edited In Response To Parent Edit: Thanks for asking! We should definitely make it clearer if there are differences per role.
This is one commonly thrown BS regarding interviews. At the end of the day it is all about one-dimensional usual algorithmic questions.
Regarding LRU cache, I think this is one of less crazy interview questions. In one phone interview, I had to solve a DP problem, code it perfectly and pass all the test-cases on HackerRank in less than twenty minutes. I am not certain how many developers out there can pass such interviews without months of preparation in such situations. Tech interviews are basically programming contests. I am not against programming contests or algorithmic questions. But it seems the interview questions are getting crazier day by day.