[Elecraft] [K3] CW "dash" sometimes inhibited?

[Mini Builder]

I should add a couple more things:
1. The "5 seconds" is more like "5-10 seconds."
2. It is happening when I'm practicing code, so RF can't be an issue. I haven't used the keyer on the air yet so I don't know if it happens there as well. Obviously, being unable to transmit dashes for 5-10 seconds is a bit of a no-go.
3. VOX is off, so I don't see how external sounds could be causing the issue.

The fact that it stops working for so long makes me think it's something other than a simple loose or dirty connection. (While I'm an EE, in this sort of situation isn't always a good thing, as I overthink the issue...)

Kurt KK6IPF