a casual link

For some reason the expression a casual link seems to have more appeal that a causal link.  I wouldn’t have thought that causal was a difficult word but newsreaders baulk at it.  Some of the results are amusing.  There is the heading A casual link between a handshake and infection. If the handshake was delivered in an offhand way, then perhaps it was casual.   Post-Traumatic Stress disorder and the Casual Link to Crime leads one to wonder if PTSD is the beginning of a slippery slope down which the sufferers slide, almost without noticing, to a life of crime.  Sometimes both phrases are used correctly.  The association between cardiac and gastrointestinal disorders: causal or casual link? But increasingly I am hearing casual link, particularly in relation to the possible connection between some of the vaccines and a rare thrombosis, where the proposal is that one is the cause of the other and so the vaccine delivery must be adjusted. It is clear that causal link is what was intended but casual link has taken over.

A contributor has suggested:

'Casual link' might also suggest in some people's minds that it is somewhat occasional or random, which fits how the rare thrombosis relates to the vaccination.

This may have been apt in the early days of the discussion of the thrombosis but as the evidence for a link with the vaccine mounted, casual became definitely causal.