This is exactly what I experienced this morning.
1. woke up PC (win 8.1, 16 GB RAM)
2. had it sit running only notepad++
3. Windows warns about low memory, wants to close notepad++ ?!?!
4. After restart and opening Task Manager I can literally watch how the Malwarebytes Service takes all the RAM available,
500 MB, 700 MB (this is where it turns off real time web protection), 1100, 2000, 3000, 4000, 8000, etc.
5. To my horror I also saw my windows explorer taking up 8GB RAM, when I toggled MB services off it calmed down.
6. MB tells me that the license server can't be reached.
7. When trying to scan it is stuck in "searching for updates..."
A clean re-install resulted in the same behavior.