Weird characters in front of sub-server names


Recently I noticed some (three) weird characters in front of the sub-server names listed in the upper left menu in Virtualmin. It’s like an “a” with something on top of it (like in the east European countries alphabet) followed by a cross sign, followed by “+/-” character. The details for sub-server shows up correctly, without those characters, they only show up on the servers/sub-servers upper left menu.
Anyone has any idea where is that coming from?