Problem 1: (MacOS & iPadOS)
The SysEx property inspector box does not reliably populate Variable Options settings. The box will save settings. If you reopen the box to check your settings, it may not bring up your current settings, instead showing default settings. If you cancel out, your existing prior settings will still be viable. If you APPLY CHANGES, ensure that the variable options settings (V length, MSB first, S length) have been correctly entered.
You don't have to open the variable options box to loose the settings. If you change the SysEx characters, it will reset the variable options even if you never open the variables inspector.
(After having MD open for a while, MD might start reliably populating the box. Once that happens, it appears to continue working properly until the app is closed and restarted. I have not been able to recreate the stimulus that causes it to start behaving properly.)
Workaround: none. There is no workaround to check variable options settings, you can only reenter what you believe are the correct settings.
Problem 2: (iPadOS)
When you open the SysEx property inspector, the save / apply option does not initially appear. The box will (mostly*) NOT save settings in either sticky or non-sticky modes.
If you enter a V or S, the variable options box will not appear to make settings.
(*Occasionally, if you enter or change an L, V, or S, the properties will save correctly.)
Workaround: If you move to the Checksum box and make a change, APPLY CHANGES (and Variable Options, if a V or S has been entered) will appear, and the settings can be saved. If you don't need/want a checksum, change anyway, then change back to none. Then make any desired Variable Options settings and APPLY CHANGES.