I’m using version 18.03.06 and I just applied all 3 of the filters, and then unchecked/deselected each one then back on. All work fine for me.
Make sure you select the clip you’re working with. Many times I’ll forget to select the clip I want to change then apply a filter to the wrong clip. There is a small check box next to the filter which you click on to deselect, which I’m sure you already know as you just tried it.
If anything else, save the project, restart Shotcut.
I restarted Shotcut and made sure my clip was selected.
The order in which the clips are selected seems to make a difference. In one instance, the Brightness filter didn’t have a problem until a value >= 120% was assigned to it. So there are definitely bugs.
I’ve used filters a great deal and it’s always from the timeline, but I can only do one at a time, then if I have to duplicate the filter, I just the copy/paste buttons within the filter window for the next clip in the timeline. Unless I’m not fully understand how you are trying to apply the filter.
Oh, and in Settings, make sure GPU Processing is turned off as that my interfere with Shotcut. If you did save the MLT file with GPU Processing turned on, there is no way to turn it off and you have to start all over again.
Bugs can’t be fixed if the developers don’t know about them. With the software I write, if there is a bug or the possibility of one, I want to know about it and address it. If it’s operator error that’s fine, but it forces me to look at the code and see if there is truly a bug or not.
If I find what I think is a bug in Shotcut or any program, I’m going to report it rather than keep it to myself. It may legitimately be a bug or it could be operator error, but that is a determination best made by the actual developers.
A few short videos I made using Shotcut with filters showing that checkbox’s do in fact work just fine.
While making the first video, I did encounter when I had all 4 filters activated, when changing Themes from System, to Fusion Dark would crash Shotcut. But I doubt anyone would be wanting to switch themes during an editing session.
We do not do anything special in the list of filters for one specific filter (Brightness). You must double-click a filter name in the filter list to toggle it. You only need to single-click to select a filter or single-click the checkbox to toggle it. Now, I just found the bug you were having: any time after you have double-clicked a filter in the list to toggle it, single-clicking the checkbox does toggle the filter but not the checkbox itself!
I was banging my head against the wall trying to figure this out as I couldn’t make this happen until you explained how it worked. I probably spent a good few hours just messing with various filters beyond what the OP had described. Then failing to recreate the bug I made the few videos showing how it worked for me.