Fame & Fortune
Where there is money to be made some form of politics and infighting are bound to occur. Many of the guilds are funded by competing nobles who view guilds as a way to gain the adoration of the common folk, who have taken to following guilds much like modern day professional sporting teams, with many being able to recall their favorite fighters kill count per delve, or their mages most commonly casted spells.
These nobles see each other as competitors and the guilds funded by their rivals as something to be crippled or even destroyed. This attitude coming from those who fund them annoy some of the guild leaders who have forsaken such funding as it “comes with a cost”, however many guild leaders happily take the money seeing it as a chance to make it big.
Behind the scenes is a cloak and dagger dance as guild leaders under instructions from their patrons attempt to lure away famous or popular guild members from competing guilds and if that fails … they could always go down in the dungeon. There are even rumors of guilds being bought out or bribed into “taking a fall” during the delve; normally this is done through feeding misinformation to the corrupt guilds parties or supplying wrong equipment to face what lies inside.