I'm using FireFox 50.0.2 (the latest version!).
When I tried to search a coin by using advanced search I got several problems.
Problem :-1-.
I'm using only LETTERING with "mokum".

Pressing SEARCH. This is the result (NOTHING FOUND)

But the country is changed to UNKNOWN.
Pressing a second time SEARCH . This is the result (1 coin found).

But now the COUNTRY is changed back to UNIDENTIFIED.
Problem :-2-.
Using the FACE VALUE I can't use the "%", Why is that now impossible. I was using it always.

Hoping those problems will be fixed very very soon.
I'm thinking that the advanced-search works only IF filled with the FACE VALUE filled exactly as it is registered. WHY is that??