OK so that is common when an object gets in the way, but there are ways to mitigate it.
Are you on default auto/settings for the camera?
You would be shocked how much the settings of exposure speed, brightness, contrast, gain, sharpness, gamma, etc. have in the ability to track.
I always knew that you shouldn't chase a bright picture - it looks nice and people migrate towards a brighter TV for example, but upon closer examination, most images need to be toned down in order to get all the details. It is even more important for a tracking camera.
You will be surprised how much changing a parameter like gamma could impact tracking. For example, if you have a pesky tree or something in the middle of the view during an autotrack like that stop sign, just by changing some image parameters you can get autotrack to pass it. Making the image a little darker at night actually helped with tracking someone across the street, which was opposite of what I thought you would think to do. So add some contrast to your image and see if it improves.
I have a yard lamp post that more times than not autotrack would get stuck on it as someone was walking and the autotrack would only go so far. Because my image has soo much contrast during the day (bright white concrete a third, blacktop road a third, grass a third), knocking down the gamma made the lamp post not be so "trackable" lol, and along with that I turned of PFA and that gave it just enough time to retrack the person walking past the lamp post.
Or put a privacy mask on the stop sign to get past it, but I prefer to not do that unless nothing else works.
Keep in mind auto-tracking is great, but it isn't perfect. Lot's of factors can influence the ability to track. They certainly are not plug and play.
It is a matter of getting the brightness/contrast and target ratio settings correct. It took me weeks and then some tweaks along the way on occasion to get mine to perform its best. Something as simple as my neighbor changing his fence from a wood fence to metal slat fence effed up my tracking and I had to adjust it to deal with it.