I have a new Roku Ultra LT waiting in a box for when my Roku 3 officially dies or becomes too erratic, but lately it is the most locking up it has ever done and it does seem like it's related to an update, but I didn't start having any issues until I reordered some tiles, more than a month since the last update in July. I'm not stuck on the logo screen but going out of screensaver randomly it will go blank showing only the theme color then reboots itself-- it held up for 5 days after I changed the screensaver from "floating circles" to "roku city".
 I notice on reboots the Roku 3 seems to struggle rendering the tiles from large mode to "small" which is what I have set for a long time. Today I also experienced the remote stopped responding but after 2 reboots it worked again (unplugging to reboot), then in one app the "back" button stopped working while it still worked inside Netfllx, a reboot fixed that too.
A lot of wonky-ness definitely happening, I even considered if it's over-heating since it's warm where I live but this issue never happens while streaming, only upon waking up or I guess messing with app tiles since deleting app or pressing * to see details also caused the lock/crash/reboot.