In Solid Explorer 2.0 same problem, as Solid Explorer 1.6
When using stock Sony remote share (Settings -> Storage -> Remote shares) and connecting to SMB server solid explorer not showing russian characters and haven't access to folder or file named incorrectly in remote directory (/storage/remote/). Problem only on Android 5.0.2, on Android 4.4.4 thats good.

I'm using Sony Xperia Z1 Compact with Android 5.0.2, Windows 8.1 with samba server. In username for connect to server also using russian charactes. Other file manager (Total Commander, File Commander show russian characters)