Lightroom Readjusts Masks After Applying Preset

I would be beyond grateful if some wonderful human here could help me with this issue which is truly frazzling one's noggin to the very ends of the earth. 

Basically this is how it goes: I make presets on both Lightroom Classic on my PC and also on my iPad. These are quite experimental for the type of work I do and involve lots of colour range masks which I add colour tinges to. On the PC all is good in the hood with saving presets, or copying sets and applying yon edits to another image. Alas, on the iPad all is not so rosey. Yes, once I apply the preset it looks absolutely fine (the same for copying settings to another image).

Where it all goes up the left is whereupon I click on the masks section, and without even as much as looking at a slider, the look of the image completely changes. Lightoom seemingly changes the location of the applied colour masks, and applies them to another part of the image. This result in colour tinges going all over the shop, resulting in images that look very different a second before going into the mask section. Nothing is touched whatsoever.

This never happens on the PC, so it's some issue with Lightroom Mobile. If I copied the settings to another Image and opened it on the PC then all would be tickety-boo and it would not readjust the behaviour of the masks.

Is this a bug? It drives me beyond bananas as I often have this perfect looking images whilst working on the iPad after creating a preset, or from copying the settings to another image. It's often impossible to get them to look right after.

Any help would be mightily appreciated!