Looks like pickRandom was deleted as a tech research option in https://gitea.wildfiregames.com/0ad/0ad/pulls/8468/files#diff-982d380b40dc36243a91196999bdea61854236ba
But I use it in DE's researchManager:
if (tech[0] == "gather_lumbering_ironaxes" || tech[0] == "gather_mining_pickaxes")
return { "name": pickRandom(["gather_lumbering_ironaxes", "gather_mining_pickaxes"]), "increasePriority": true };
if (tech[0] == "forge/techs_forge_cost" || tech[0] == "forge/techs_forge_speed")
return { "name": pickRandom(["forge/techs_forge_cost", "forge/techs_forge_speed"]), "increasePriority": true };
Could this cause the problem? I really want the AI to choose a tech out of these pairs. It worked well enough in R28. If that's true, then base game's researchManager is bugged too at line 91:
if (tech[0] == "traditional_army_sele" || tech[0] == "reformed_army_sele")
return { "name": pickRandom(["traditional_army_sele", "reformed_army_sele"]), "increasePriority": true };