I'm sure you have encountered a lot more bugs during the game (even though you may have not noticed them). See the installation document attached to the mod's readme file (
link).
Tactics and Item Upgrade mods are incompatible with Improved Anvil. You have also installed two incompatible components of Ease-of_Use plus several other components which are not recommended (as you can read in the installation document). Valen and solaufein NPCs are not recommended either. Your current problem, however, relates to the Tactics mod.
Solution:
Uninstall Tactics and return to a saved game in the elven city before going to face Irenicus at tree of life.
Note: You should uninstall
all components of Tactics (not just the component which improves Irenicus).
You have actually played the entire SOA with a bad installation. To get rid of all of the potential problems, you will need to uninstall all those incompatible stuff and start a new game; but for now, you at least need to uninstall "Tactics" to solve your current problem. Next time, read the installation instructions carefully.