(I can't find another report, so forgive me if this is a dup). Encounterlog only shows PLAYER_INFO abilities for the person who created the encounterlog.
This is from my HA sorc logging an rnd, there is an entry like this for each player for each encounter:
21266,PLAYER_INFO,1,[142210,142079,63601 [...skipping 1000 characters...]] 373,BERSERKER,T,16,LEGENDARY]],[42060,39018,61505,77182,77369,23492],[39018,42028,23231,77182,77369,23492]
Those last two sets of six numbers are your front and backbar ability IDs. Last update every player logged a PLAYER_INFO line that looked like that. Now the players who aren't the person logging have a PLAYER_INFO line that looks like this:
268,PLAYER_INFO,32,[142210,142079 [...skipping 1000 characters...] BERSERKER,T,16,LEGENDARY]],[0,0,0,0,0,0],[0,0,0,0,0,0]
i.e. other players' slotted abilities are all zeroes.
So services like esologs have no way to work out what abilities those other players have slotted.