Planar Wrack is one of those spells that has multiple maintained icons. You get one icon when you cast it, then when it lands on a mob, you get another icon (the one with the green Prestige number). When you use "fixed tiles" mode on the standard Maintained Spell Monitor, all maintained icons that have the same name go into the same tile slot
. So that's why the Prestige values appear sometimes and disappear at other times.
The Lite monitor only uses stacking (separate) tiles, so you should always see all of the the icons and counters. If you want to experiment with the full monitor, change the display to one of the stacking modes. Planar Wrack Prestige counters are tracking exactly with the Maintained window for me, using either version of the monitor. I haven't seen it jump from 1 to 3 -- could that be from a doublecast landing?
PS: The "standard" (original) Maintained Spell Monitor code hasn't changed in about two years. Version numbers have been going up only because the "lite" version was introduced earlier this year.