Not sure if this is a new problem with 2.2.3.1 or if it existed in 2.2.3 - I've only started mining Truesilver today after installing 2.2.3.1 - but it appears that Gatherer is not showing Truesilver deposits on my map or minimap. Other ores and deposits display fine, and the Truesilver is apparently being recorded OK - the number of Truesilver deposits appears correctly in Search and Report - but the locations just don't show up on the maps.
check your filters, 2.2.3.1 prints a message if unable to record (sometimes a bit too often since it's based on spellcasting events and some mix up in the flags happens from time to time).
hm, click on the reset button under the ore filter in the filter tab, see if that does something.
also check if you have rare ore checked in the general tab (normally not necessary).
and as a last resort (before having to ask for extracts from the savedvariables), see what happens when you disable mithril and/or truesilver in the filters.
next will be to check the truesilver entry in the data and verify it's all in lower cases.
Just FYI, I had a similar problem after upgrading to 2.2.3.1 -- neither Gold or Truesilver was displaying. The reset button for Ore didn't work. For me, simply disabling and immediately enabling those filters made them show up; if anyone else has the same issue, I'd certainly recommend doing that.
the reset button works only on individual item filters, if you had to take the whole categories off/on, that was the general category filter (ie. ore, herbs, treasure), just to clarify when I mention check the filter that include checking from the top (minimap display, category display and then item filters).