I agree a visual indication for > 3ms inserts residing in a (partial) low latency path is a must. I think red is a little confusing though.
A plugin with a latency > 3ms, residing in a low latency monitoring path, is not being bypassed, it just isn't mirrored as monitor FX on the low latency path (in the background). So a > 3ms insert residing on a bus that is processing a low latency (monitored) and high latency (playback) signal, still processes the high latency signal. So it not entirely stopped processing and therefor the color red may be misleading.
In the example below the > 3 ms latency insert (blinking) on the Bus (3), still processes the signal from the high latency channel (2), while it temporarily does not process the low latency channel (1), because it (the > 3ms insert) is not duplicated to the Monitor FX channel of the low latency path.