An Odd Psycho-Phenomenon noted in a Jamaican Client

I’ve been dealing with a well educated, upper middle income woman in her middle years for the past 10 years.  She’s doing pretty well and comes to me for short follow-ups now and then when she manifests a peculiar lexic phenomenon apparently orchestrated by her subconscious mind. 

At various times in her efforts to master her ‘downside’, as she calls it, she might be reading or having mental conversations with herself in which she does a lexic switch the like of which I have have never heard or read.  She uses it as a sign that she is migrating out of  a rough patch even if she is not consciously registering that she is stressed so it’s her signpost that she is adjusting  productively and positively.  When she deals with the stressful situation or trigger, her subconcious stops pulling this trick on her.
Under stress her subconcious finds an almost exact homonym that means the exact opposite or is a perverse aberration of the intended word.

Eg.  ” I serve God” becomes “I sever God”

” I’m going to meditate” becomes “I’m going to masturbate”

I’d welcome an opinion on what this phenomenon is.