Jc5 130 stuck in gear

[Idonkinv]

Just asking around if anyone has a similar problem. So the car gets stuck in gear 4th I believe when the car is stationary going into reverse. Now I know its easily done if you're going quickly but I make sure to take the time with it. It's done it twice and everytime has been on a gravel carpark, I've made sure I'm dead still too before trying reverse. Reverse plenty of times on tarmac/drive and its been fine. Any suggestions on how to sort it as I have to take the end casing off each time. Any info would be appreciated 👍🏻 it's a JC5 130