Scottish Gaelic: do myself a big mistake

[Alxmrphi]

I was watching a bit of BBC Alba before and there was a cooking programme on, subtitled in English, and the woman who is hosting the show moves away from one of the contestants and says something like "I should move over here now", followed by "before I do myself a big mistake". I was a bit "Ehh??" because usually even for any TV translations, they don't usually make weird mistakes like this, then that coupled with the fact that Gaelic speakers are vastly vastly bilingual and have such an intimate connection with English, I was surprised a mistake like that would be made by the Beeb. So that led me to the conclusion that this literal expression must exist in Gaelic, and therefore is possibly said in their speech of English, too. So the existance of one means a sort of calque which has jumped language. All this is speculation, so wanted to know if anyone can confirm this.

Does a similar literal expression exist in Scottish Gaelic that could explain this (what would be considered in Standard English as an) error?
Does this expression (now in English) exist in some areas of Scotland, and is its origin in a calque translation from Gaelic?

Any information to satisfy my curiosity is appreciated
Alx

 

[L'irlandais]

Hello Alxmrphi,
In the absence of huge numbers of Gàidhlig-speaking members, I will hazard that it's perhaps a turn-of-phrase loosely based around "before I do myself a mischief" crossed with "make a big mistake" (both very English expressions). I know that in Hiberno-English the phrase wouldn't raise an eyelid, there may be a tendency (in Munster anyway) to avoid clever turns of phrase in English, even when known by the Gaelic/Gàidhlig-speaker.

In colloquial speech "do someone a mischief" comes originally from Middle English (from Old French meschever = come to an unfortunate end)