Following the discussion about the sticky ear hooks I paid more attention to my cable and realized that is was getting pretty sticky again and a closer look showed liquid inside the ear hook tubes.
I put it in a ziplock bag with plenty of silica gel and will check if that fixes the issue. Will report the findings.
On the subject of removing the cables I actually found that if I pay very close attention to pull exactly along the axis of the connector, the cable releases without much problem. It’s not easy to get it right, especially with the IEMs being difficult to hold securely, but I never had to pull too hard. If it doesn’t move, let go and try again. Worked for me every time on IER-M9 and IER-Z1R