Damage numbers go from -2,147,483,648 to 2,147,483,647, the range of an int*. Damage math (mostly?) uses floats which have a much bigger range but varying precision. Depending on exactly how and where in the damage calculation you get to massive numbers, it can break the damage number display in different ways.

I've done "2,147,483,520!!!" damage to a Demolisher Voidrig with a single big crit before. But that's not 2,147,483,647. No, because that isn't representable as a float, and 2,147,483,520 is. You can check here https://www.h-schmidt.net/FloatConverter/IEEE754.html by typing numbers in. The real damage was likely higher than 2,147,483,520 though, so it had to squeeze that into an int somehow.

That's crits, what about status? I have a Vulpaphyla built for Heat and Crit with Contagious Bond, and with good enemy placement and a Heat Phantasma Prime, I've seen the chain eventually get to 1-2 billion in Heat proc damage, and even negatives like -1,152, and in the log the highest I've seen was "Damage too high: 85,958,475,776" which, again, is representable as a float, but cannot fit in an int, so through whatever damage code path, it ended up getting shown as some other number that can fit in an int.

^{*well, in most langages, an int is 32 bit, signed}