Thanks for checking it.
Can you execute the following commands and share the output of it with us?
find ~/.bitnami -maxdepth 4 -type d -ls
cat ~/.bitnami/stackman/machines/mediawiki/metadata.json | grep requiredMemory
Can you also try a full uninstall of Mediawiki and install it again? The following guide will help you to do so:
Uninstall The OS X VM.
Note that deleting
~/.bitnami will delete other OSX VMs that you may have installed.