Same here. I updated to 10.3.1 and multiple issues have arisen.
1. Scan durations have increased dramatically. Previously Windows assets took 45 seconds or so. Currently scans take 5+ minutes per device.
2. Disabling scanned item interval doesn't exclude from scanning server scans or from History even when unchecked.
3. Domain credentials would not detect credentials so after digging through forum posts someone said to remove any preferred domain controllers and add them back later. That fixed it so thank you whomever you are.
I will say the UX and feel of the web gui is the best I've version I've used, not much lag and moving from link>link is fast and smooth. My only gripe since I use LS all day is I wish I didn't have to type my orgs pc location/device prefix info just to get the last 3/4 characters. You can do exactly this when at the deployment page>deploy now>selection instead of typing AB123-PCINFO999 you can type 999 and get any asset with 999, extremely useful and time saving.