Sounds like it could be a connector issue. Have you re-pinned/replaced any connectors on the mpu, lamp driver, solenoid driver, or rectifier board? Are the boards original?

I'm thinking the wires are in the right spots on the connector, but a bad pin on either the lamp board or mpu board (there's a connector between those 2 boards) could cause the wrong signal to occasionally get sent and processed as the wrong lamp (in this case, the signal getting sent is turning on the special lamps)... For instance, say the signal between the mpu and lamp driver is supposed to be binary "0110" for the correct lamp, but the 3rd data pin is not making a good connection, so the mpu/lamp driver processes the signal as 0010 instead, which could potentially trigger another scr on the lamp driver instead. When the connection is making better contact, it may be receiving the proper signal and in turn activate the correct SCRs causing it to light the correct lamps. This is all based on a rudimentary understanding of this stuff, so please don't take this as gospel... Just what I'm thinking could possibly be happening.

Couple possibilities here: the resets could be due to a weak 5v supply for the mpu. Sometimes a coil firing can be just enough to lower a weak 5v supply to the point it triggers a reset. Also make sure your tilt and slam tilt switches are properly adjusted as well.

As far as the lamp problem, it looks like the connectors i am referring to are J1 on the mpu and J4 on the lamp driver board. If male pins have already been replaced, i would also recommend be female connector pins as well.
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Have you done any work on (or replaced) the rectifier board and/or solenoid driver board?

If you have original connectors on both of them, i would start by re-pinning (or replacing) the rectifier board, new header pins and new female connectors.

The 2 smaller 0.100" connectors at the top-right of the solenoid driver often need to be re-pinned as well. There are also a couple suggested modifications to make on the solenoid driver to reinforce the ground and +5 volt connections at the board too.

There's also a big capacitor on the solenoid driver for the 5v circuit that may need to be replaced as well.

One other thing: it appears there is a switch on the same row as the tilt switch that uses a 0.5uf ceramic cap. If that cap is original, it could be the source of the intermittent resets too. I'm not convinced it's necessarily the culprit, but if that caps is original you can start by clipping a leg off it and see if that corrects the issue. If it does fix it, it's still recommended to replace it. Here's the row I'm talking about, note the cap on the last switch in the row, for the right pop bumper:

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