EOS 80D shutter malfunction

[classicalrhino]

My camera shutter is malfunctioning. I can take normal photos and videos, but every now and then, the camera will rapidly click. It doesn't take any pictures, but the camera is trying to do something. It will also do this if the camera is switched off and the battery is still in the camera. It especially does the clicking after I try to focus the camera using the shutter button. I turned off auto cleaning of the sensor, and this problem still happens. It also still happens on both manual and auto focus. I have attached a video from my viewfinder to show what is happening: https://www.youtube.com/shorts/cX-8-ChK7IE 

How much would repairing this cost? Do y'all recommend I send this in for repairs, or should I get an upgrade/a new camera? My camera is approaching 10 years old, and I use it a lot for birding to help ID birds and to get good pictures of them. The lens on the camera is Sigma 18-300mm lens.

Thanks for the help!

[classicalrhino]

Hello! Thank you for your advice! I have a Sigma 18-300mm 1:3.5-6.3 DC lens. I tried doing the tricks you suggested, but the clicking keeps happening at random times. The frame in my viewfinder physically moves when the clicking happens (it shows up really well in the video link I included in the initial post), so it's not just a sound.

[ebiggs1]

"If it has IS that may be malfunctioning, sticky aperture blades might alse be a problem."

The lens may very well be the problem. However, I do not think it likely is "sticky aperture blades" and even less likely it is the OS (Sigma's stabilization is called OS not IS). If it is a Sigma lens problem it is very much more likely to be a FW issue.