i finally solved my buggy architect fights. the only problem being that it requires a change of difficulty setting. I too was getting the same issues mentioned in this thread and expected it to be patched by now.
Just on my second playthrough and fought all the architects without issue. Bit annoying though because I am on hardcore and want to do an insanity run next but even with level X and the highest mods and armor, I struggle to do any dmage against the architects whereas even the ascendants die easily.
i switched to narrative and can kill it within a few shots without dying. then put it on any level from normal upwards and you get it the loop and cannot trigger the opening of the legs or head conduits. i did find that loading an early manual save got me back okay but then the same problem, the thing requires so much damage on normal and above that there is a good chance of dying especially with the minions that trigger every so often. Its annoying though, I completed the others on insanity and want the achievement but changing it mid-game means you can't. I was willing to pesevere in the last part of ME3 with the gun batteries but don't feel the same with this game, the architects feel like a cheap cop out to me.
i can't remember if there were ever any problems similar on the Reaper child in ME2? that was a similar concept, well the same albeit with different boss and minions but at least it wasn't a bullet sponge like the architects are !!