Quoting from a sentence in the first paragraph of 802.1AB-2016 clause 6.7,
"It follows that each LLDP agent makes use of a unique MSAP, and that the agent can be uniquely identified by the receiving agent using the MSAP’s identifier as specified in 6.2." Figure 6-2 verifies this sentence. If a system implements multiple LLDP instances on a port, each one requires its own MSAP, and thus, its own MSAP identifier, which is a MAC address.
Quoting from the IEEE Standards Association's "Guidelines for Use of EUI, OUI, and CID" (https://standards.ieee.org/content/dam/ieee-standards/standards/web/documents/tutorials/eui.pdf):
"With the exception of such protocol identifiers, EUI-48 identifiers are still intended to identify items of real physical equipment or parts of such equipment, such as separable subsystems or individually addressable network ports. The expected use should not exceed one EUI-48 identifier per hardware subsystem, or at most a very low number of EUI-48 identifiers per physical instance of such equipment (e.g., groups of ports as in IEEE Std 802.1AX, for link aggregation). Allocation of a single EUI-48 identifier to identify or permit addressing of a fixed and permanent function associated with a real item of physical equipment occurs for the lifetime of that equipment or an indefinite period of use."
That is, the RAC prohibits (very appropriately!) using MAC addresses to identify software constructs, which multiple LLDP instances certainly are.
I do not believe that there is any justification whatsoever for this requirement for multiple MAC addresses for multiple LLDP instances, as the LLDP makes no use whatever of the source MAC address in an LLDP frame. One could, just barely, justify the extra MAC addresses required for multiple agents on one physical port using the "or at most a very low number" of addresses phrase in the guidelines on the grounds that you expect to implement at most two or three agents on one port at different reaches. But, if unicast addresses are used as destinations for agents, then the number of MAC addresses required per port can be as large as the number of other devices that could be attached to the bridges LAN, and that is absurd. For that matter, even for the two agents with two reaches case, from where does this extra MAC address come?