Slow download but ok upload

Hello again,
I’ve been recently having an issue with 2 ROV’s where they are running into an acceptable upload of about ~42mbps but a rather poor download of 18-22 mbps, with one having visible dropouts on the download which looks like this

Has anyone run into this and knows how to fix it?

I’ve currently tried bypassing the ethernet switch (checked to make sure it wasn’t one with the faulty part already) from the ROV, putting in a new fathomX, different tether, tether on other machines works fine.