I marked this as a duplicate of #216864 as I think it is the same issue (the problem seems to be in the localization part, starting with "LANG=C gcalctool" doesn't show the bug)
I marked this as a duplicate of #216864 as I think it is the same issue (the problem seems to be in the localization part, starting with "LANG=C gcalctool" doesn't show the bug)