Data Validation strange behaviour

[ViktorVanRiver]

I’m trying to create a dependent drop-down list. In one cell, I have data validation with a named cell range. Right next to it, I have an INDEX MATCH formula to return a value based on the first cell. However, when I try to use the drop-down list, they copy each other and everything breaks. Previously, I thought I was using the wrong formula, but it happens no matter what formula I’m using.
Problem.ods (14.4 KB)

[Zizi64]

Here is a possible solution:

Problem_Zizi64.ods (15.4 KB)

[ViktorVanRiver]

If data validation source set to cell range and there is some formula, in neighbour cell it changes to same data validation source, even if it set to cell range, however every entered formula works, but not too long

[PKG]

You are looking for rows although you want columns.

[ViktorVanRiver]

Solution was found: untick “expand formatting” in calc general settings.