Is this expected?

I have an 8-port TP-Link gigabit switch and only ever saw 100Mbs on anything connected to it.

I checked the cables but had missed a short Cat5 cable to my DVR on 1 port.

Switching this to Cat6 and now everything is running at 1000Mbs.

Can 1 cable impact all ports on a switch even if everything else is Cat6/6a?