Network MIDI Session with Pro Tools causes Excessive Memory Load

[RTGraham]

Anybody else seeing this, or anything similar?

I'm working in a studio where up until today, we had no problem sync'ing machines via Network MIDI sessions. (Inside the Audio MIDI Setup app.)

Today, though, if I link up my MacBook Pro to a studio desktop Mac via Network MIDI, then launch Pro Tools, the local Pro Tools running on my MPB becomes super-sluggish and eventually gives a message that physical memory is critically low.
Disabling Network MIDI returns operation to normal.

This is all on wired Ethernet connections. It seems like something's going on here in the building where IT has been revamping their network structure and my MBP may have gotten its IP address reassigned a couple of times over the course of a few hours (before today, it would retain its DHCP-assigned address for days if I didn't reboot) - but this happens right after a fresh reboot.
It also seems like a couple of in-house Macs in other studio rooms may have been renamed and there may be duplicate names on the network, but I don't know whether that would be a factor or not.

Whatever is going on, though, it seems like some kind of feedback loop or data bottleneck: what we've been using Network MIDI for primarily is to link up music playback machines with video playback machines (in scenarios where satellite mode sometimes won't work) while working on some scoring - and if I try to enable Network MIDI after a session is already open, and then jump around the timeline on the music machine, the video-playback machine gets stuck jumping to the same location over and over even after I disable Network MIDI - as if it's still receiving a constant stream of instructions to relocate.

Any guesses as to why this is suddenly happening?