PHPredis fails to Set, where Predis works fine... Any suggestions?

[j-fulbright]

We are wanting to move to PHPredis since it is the recommended default now, but am running into a case where it is throwing a random error about being unable to connect to the server.

We are using this method: Redis::set($redisKey, 'test', 'EX', 1800); which works fine on Predis.
I have even tried Redis::set($redisKey, 'test', 1800); and it throws the same communication error.

I'm running redis-cli monitor and can plainly see it trying to do something when it hits that command but it just blows up.

There are other places that call Redis::set and those seem to function as expected, but I'm not seeing any differences anywhere.