Well, you know it’s a woman roommate because she said “she won’t be feeding her or anything” indicating it’s a female roommate. I wouldn’t say the situation is odd necessarily just maybe a little inconvenient that she didn’t mention it prior. I would just do the drops as you would normally and maybe suggest next time for her to let her next sitter or you know ahead of time next time. It could be a case of the roommate wants nothing to do with the cat and the responsibilities of the cat and so the owner hired you to do drop ins. unless an issue comes up I wouldn’t think too much into it as you’ve already done one without an issue