Some addon authors may set the map to the current location in order to update some of their routines. Originally, this went unnoticed as the WorldMap disabled the rest of the UI when opened. However, as MetaMap enables the rest of the UI for full interaction, those addons will cause the map to jump back to the current location.

Known addons which cause this are:
Gatherer: Latest Gatherer version fixes this.
MapNotes(pre 1800): Do not run MapNotes alongside MetaMap.
MonkeySpeed: Still awaiting a fix from the author.
Speedometer: Also affects Gatherer - status unknown.
BiBmodwindows: Mod no longer in development
StatusWindow: Author is looking into it.