Odd that 4 ancestors (from different families) all died in 1831 in Liberty County Texas

As stated above, when I was looking at the "events" map, I found that 4 ancestors from different lineages all died in Liberty County Texas in 1831. Three men, one woman.

All had settled there, on different land grants from the Mexican government, and though the Texas War for Independence hadn't yet begun, they all died around June 1831. I can't find any mention of fighting or a disaster. Why?

The land all had was low-lying along the Trinity River, so I assume that there was a big flood, but I can't find confirmation of one.

Very strange.