The Scan Locations and Exclude Locations of Real-Time Scan that can be configured has been limited to 30.
The aforementioned values are hard-coded so it is spec. This is because, for Real-Time Scan, those lists will be passed to the Kernel Hook Module (KHM), which is running in kernel memory space. So the number of items on those lists have been restricted to get a better performance.
As a workaround, you can use wildcard * to exclude the folder that starts with the same characters. For example, if you want to exclude /tmp/folder01 - /tmp/folder31, then you can add the exclusion as: