RATS... Hope you are OK... Going over the bars in traffic is bad!
Many times I have had loose retainer nuts on my presta valves. Is the valve stem hole worn? Is it possible the valve snapped from wear movement from the rim?
Anyway, here's another thing on my Pre Flight Check List.
Make sure the presta valve nuts are tight and not worn. Thanks.
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No matter where you're at... There you are... Δf:=f(1/2)-f(-1/2)