We received your email Lishan and I got a reply out to you. This is an issue that has been known to happen. It happens right over the hyper violet LEDs that are in the Iridescent Booster upgrade. That LED color is a bit sensitive to having salt residue on the splash guard, which causes the light to reflect back through the splash guard, and it bounces back and forth and heats up the splashguard in that specific region. This only happens with the Hyperviolets.
Good news is that we have finalized a relatively easy and inexpensive permanent solution for this, and it should be available by the end of this week.
Jeff