Query variable value not changeable in default section during query navigation

Hello experts,

I have basicly the same issue that was dicussed here: https://archive.sap.com/discussions/thread/692306

But it seems that no solution was found and that this issue is quite old.

Minimal Working example:

1. Create a query
2. Filter a characteristic (e.g. 0CALDAY) in the default filter section by a variable with option: greater or equal
   
3. Execute the query and enter an arbitrary value for the variable
4. After executing the query, reopen the Variable Prompt. The variable value cannot be changed anymore.

As soon as I either change the option from '≥' to '=' or if I move the variable from the default filters to the global filters, everything works perfectly fine.

As a workaround I was able to specify an intervall [Variable - 21.12.2999]. But this solution isn't really sexy.

Is there a better way to do it? Can this be considered a bug for SAP?