Not entirely sure if I should be posting this in this sub-forum but it only appears to occur in games against AI and I couldn't find any accounts of it from some quick searches.

Very occasionally heroes that the AI select do not appear in the top bar, I thought that maybe there was only one bot in the game however it was a full team despite only showing Tidehunter. It is not the first time it has happened either, it seems happen randomly despite not doing anything different to normal.