My first speed was replaced some years ago because it leaked. Now the replacement did this. It isn't leaking yet but failure is imminent! What would cause this? I guess I'll put in a GPS speedo soon. Are they liquid filled also?

GPS speedos are not liquid filled.

That’s bogus it shattered like that. Shouldn’t happen.

Well, very top of gauge says Autometer Products Inc, Pleasant Grove, UT . If Livorsi has no answer/fix then maybe worth a call to Autometer and see if they have an answer and a fix ?
No, does not appear to be liquid filled.

Autometer has an amazing redo dept, they redid all my cig gauges years back and it was fast, cleaned faces and new needles. price was right on point as well. mine were older gaffrigs, call first I think they were doing away with repairing other brands, but worth a call.

Ive also seen plastic do things like that when exposed to UV for long periods of time......the natural oils leave the plastic and it becomes brittle...a little pressure and it will craze up like that.
I always had a beach towel covering my dash when we are anchored up just so the needles don't fade to light pink....also doesn't hurt to put some car wax on the gauge faces if the lens' are plastic.

Those lenses are very prone to crazing.
I have used this guy to replace mine that did the same thing.

GuageSaver.com, Eric Clayton.
Includes instructions for removal and replacement.
About a 10 minute job.

Interesting responses. None of the other gauges have done this, just the liquid filled speedo. I'll look into my options this winter

Clearly you were going so fast you exceeded the gauges capacity!

I had Autometer redo a few of my gauges also, although mine were Autometer, but they were very easy to deal with, quick, and fair.

Exactly what you said. Mine are always covered with a towel when we are tied up. Also mine get wiped down with Meguiar's spray wax since I use it on all the gel / painted surfaces. Those UV rays are a killer on the gauge lenses and faces.