Pass The Mustard

[MrTwatchester]

I just saw this in an email, but it's kind of a charming eggcorn really, as it makes sense as a phrase (if passing mustard is a thing that has a protocol, like passing a joint. Or port).

I think this may be a bastardisation of 'pass muster'.
Muster was an assessment of turnout in the armed forces. If your uniform/equipment, etc was not up to standard, you were in trouble!
We now use it to mean, someone/something has failed at something, or isn't up to scratch

In what context were they using the phrase?

I suspect it falls into the 'escape goat' trap.