My left rear did pretty much exactly what you describe. I went out from work to lunch it was down. Drove, came back 2 days no issues (ordered bags day 1) deflated once a little 4-5 days later. When I got it out it had damage at the fold so I guess it was folded on the holes when it held.

Good luck hope you don't have any more issues.

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BMWCCA # 480346

'72 e6Tii rip
'90 e30iC sold