Ok, I bit the bullet and started deleting old versions. It didn't seem to be an issue with too many characters. I deleted a bunch of old, different characters, and that made no difference. It did seem to be an issue with too many copies of the same character. I started deleting old versions of this character (I use a lot of mods, so I make a lot of backups). As I started deleting copies, all the imports I had been making over the last few days started appearing. They were in the vault, but not displaying. I deleted all those extraneous copies I had attempted over the last couple of days, and got the number down to around half a dozen. Now it works just fine. FYI, I tried different browsers, but that didn't change anything prior to deleting copies of my character.