Can't enter the text "XMP" followed by colon

It’s impossible to enter the text “XMP” followed by a colon. When I try to type the text shown in this screenshot:

the forum converts it into “XMP.” (“XMP” followed by a period).  Copy and paste doesn’t work around it.  But you can enter it into a Code box:

XMP:AlreadyApplied

In the Lightroom and Camera Raw forums, it’s relatively common to discuss metadata issues, and XMP<colon> is a frequent prefix for important metadata fields.

A little experimentation shows that typing “P” followed by colon always results in “P.” What is so offensive about P<colon>???  Did high schoolers code the forum platform?