It sounds firmware related but it’s really difficult to know what the issue is, only that as you’re aware, the behavior is abnormal.
Does it do this in all projects, or only your current project? Has it only started happening since the firmware update? Did it only start after you loaded some new samples into the plus drive? What are the conditions under which the problem started? When you start it up in pre-boot mode by holding down the function key while powering up, does it list any errors? are any of your samples garbled or missing? are any of your projects unloadable?
If you’re getting no errors, start small. Verify whether the problem exists in all projects. If it doesn’t, there may be an issue with the project you’re working on currently, if it does happen across all projects make sure your data is backed up and try reloading the OS. Starting small will help you figure out what is not the problem, and help you figure out what direction to go in next.
You can start a ticket with elektron, but you’ll just be waiting for a reply and still have to deal with the behavior of the machine. If you do some of your own troubleshooting and it doesn’t fix the issue, you can at least relay to support what steps you’ve taken so hopefully they can get you a resolution faster.
It’s highly unlikely your issue is hardware related, but what you’re describing is very odd so clearly it’s not supposed to do that. Good luck, let us know if you make some progress or maybe someone else will have some other advice but generally speaking, if you can’t easily resolve it with basic troubleshooting you probably need to file a ticket with support.
Just to make sure, did you go onto the source page of the next pattern and make sure the sample number is the same for each trig? That they correspond to the other pattern?
So just for example (with the sequencer stopped), look at your sample number on the source page for trig 5, then go to the next pattern and on the source page does the sample number match? is it possible the sample was accidentally changed?