Blown driver

I recently blew both of my 6.5" drivers and cant figure out why.

I was driving along and they were acting normal. The sub went off and a second or two later the 6.5" speakers started clipping. Clipping real bad (square sine wave). My friend and I cant figure out what caused it. We have one theory but it isnt at all a strong one. Our thought is this. The sub went off because the gnd and power connection came lose and fell off when I took a sharp turn. They contacted and caused it all. That should have blown my fuses in the power wire though if anything.

Any other thoughts?

Here is the setup:

Speakers: SLC 365

Amp: JBL CS60.4 (60x4@4ohm / 140x2@4ohm) bridged. Gains are at 4V

Head unit: Not sure on model, lower end pioneer 4V RCA outs volume at 25

Sub: older kenwood 300W RMS

Sub amp: older kenwood 600@ RMS Gain at 3V

When we checked the JBL amp there was one blown fuse on it.

The amp still works fine so do the X-overs 4" drivers and tweeters

The sub is fine and the sub amp is fine?

After typing this out and reading it I also think the 6.5s might have ad a manufacturing defect?