I have recently unpacked my copy of the 4th expansion, Imperial Rome. There are tan blocks that are supposed to expand the Eastern Army... but they're completely different from the blocks I got in expansion 1. As you can see in the photo, the ones from expansion 1 are "woody", the new ones are yellow. The new ones are also much bigger. Is this normal? I asked GMT about it but didn't get any answer until now.
That is indeed sad truth. While ok for Warriors, LBC does not look nice. Use the spare blocks in original color and the "yellowish" only when necessary. When playing, kill always the yellow ones first.
Mine were mismatched in colour (less than yours) but not in size.
I was lucky enough to get them all at the same time so I could allocate all of one style to the same units. i.e. the yellow ones are my slingers, Light Bows, and Cataphracts. All the rest are original set.