Two glitches -
First, attaining total victory without any level 3 allies on Initiate Rank 3 causes the game to freeze on the victory banner. Abandoning the ritual functions to return to the main menu, but it doesn't recognise or save my progress, making that attainment unattainable.
Second, using the Demi Summoner and the right distillments, it's possible (if unlikelY) to summon three level-one units in a row in the middle of combat, causing them to merge and level up just as they would during prep time. When this happens on the computer's side of the board, the game proceeds as normal. When it happens on my side, it freezes.
Finally, I'm not sure if this is a glitch or not, but it's possible for a summoned Demi Summoner to die and summon an adjacent Altar Beast, which then recognises itself as a new summoned unit and buffs the Demi Summoner back to life again. That... seems like the wrong order. o_O
Otherwise, I'm having a lot of fun with this.