I have 11 explorers & 6 Geologist - all at varing levels of training.
But comparing their already learnt skills against the achievements there seem to be several occasions where invested skills are not being recognised.
The explorer skills I have identified as not being recognised so far are:-
Bean-a-colade ( I have 2 Savage scouts with this skill)
Sophisticated Pillager ( I have 1 savage scout with this skill)
Trouble-Seeker ( I have 5 Codex on Savage scouts)
Pathfinder ( I have 9 Codex on Savage scouts)
Loot Waggon ( I have 6 Tomes on savege Scouts)
Travel Expenses ( I have 3 Tomes on one of my Savage Scouts)
Deforestation ( I have 3 Tomes on one of my Savage Scouts)
Fearless Hiker ( I have 7 Manuscripts invested in my Savage Scouts)
Mountain Boots ( I have 20 Manuscripts invested in my Savage scouts)
This isn't just a problem with Savage scouts as I have got the acheivement for the Extended Weekend where I have 11 tomes invested in my savage scouts..none on my normal tavern explorers.
For the Geologists the identified achievements, i have found so far, not being recorded properly are
Copper Mining Surplace ( I have 3 jolly geologists each with one tome)