Monospace macro mangled on save when it contains multiple escaped underscores

Wiki markup:

{{\_\_CLASS\_\_}}

Expected output: (with two underscores on either side and monospaced)

__CLASS__

Displays correctly when previewed but is then mangled when the document containing it is saved. When the document is retrieved again, that segment has been changed to the following.

Wiki markup:

{{\__CLASS_\_}}

Actual output: (with one underscore on either side, monospaced, and italicized)

_CLASS_