I noticed a missing glyph in the Logos 5 default font. The glyph is ̓, which I think is U+0313 (combining comma above). The glyph is in the Logos 4 and sans-serif fonts.
You can see the missing glyph in BDAG, here: logosres:bdag;hw=$CF$84$CE$B5$CC$81$CE$BA$CE$BD$CE$BF$CE$BD;off=902
There appears to be a second bug in that if you search for the word with the missing glyph (FFr̓vig), Logos returns zero results. It should obviously return at least the result in BDAG.