What is your operating system?
Windows 10
What is your Shotcut version (see Help > About Shotcut)? Is it 32-bit?
21.05.18
Can you repeat the problem? If so, what are the steps?
(Please be specific and use the names as seen in Shotcut, preferably English. Include a screenshot or screen recording if you can. Also, you can attach logs from either View > Application Log or right-click a job and choose View Log.)
Make an MLT with multiple video clips. Apply multiple filters to the output channel so the filters apply to all clips. Then start a new MLT and import the MLT as a clip. The filters will be duplicated and stacked on top of each other times the total number of clips making a crazy looking video, totally different than the original MLT.
I discovered this because my GoPro and drone both separate continuous shots into several files. I tried to join these files to apply one set of white balance and color correction filters to use the continuous footage MLT in other videos.