ADTRAN only implemented the Static form of LACP. This means it cannot negotiate the connection. Many other products will only do dynamic or negotiated LACP, and this does not work with the ADTRAN implentation.
P.S The EMR R11.10.x has bug fixes that are not always in the Feature release since that is based on much older code usually.
For more infromation -
Link Aggregation Control Protocol (LACP) in AOS
Thank you. I ultimately realized that. I had read the manuals and tech specs for all products involved, but I didn't realize the distinction between the LACP types. I was originally (improperly) thinking LACP meant LACP... not that there were various implementation types. I appreciate the feedback.