Good morning,
I have this issue.
I, too, thought it was a fault , and when I took it to Wessex garage, Bristol, they were intially unaware of the issue but confirmed it is an actual known fault (there is a data/fact sheet from Mazda).
I was informed that the in 5th gear the gearbox vibrates enough to "push" the gear stick out. Not ideal 70mph. I was informed, via Wessex Bristol, that to replace the gearbox would be....£2,500 with an additional £700 in labour.
Stunned, I declined. It was a 2nd hand and cost twice that when I purchased it.
When I got back to reality I questioned why there isn't a recall on the issue, and I think, and please anyone correct me and advise how I can challenge this, but as it's not a safety issue, or resulted in numerous dangerous incidents, then there is no reason to recall.
However, I, like others use 5th rarely, (but to be honest, the underlying issue of it popping out adds to that).
Anyone else.
C.