I tried the tutorial again from the beginning, and I may have found why 51st was so slow to attack (I may be wrong though). So what I did was to send 51st and 318th at the Steinbruck Bridge but without sending B.35 tank and B Battery, and they both made their assault as expected. I think that what could have happened before is that I sent B.35 Tank and B Battery to soon, and it may have interfered with the assault of 51st battalion. I tried a second time, adding B.35 Tank and B Battery to the assault, but much later than previously (after 51st was engaged with the first German units). Again, 51st behaved more as expected. Is this plausible? Anyway, I'm still learning, and as I could see there's a lot to know. Finding the best tactics is part of the fun, but I will have to get used to this real time concept and autonomous AI commanders.