LHG 5XL slow forwarding

Hello
I’ve got 3km long wireless link between LHG 5XL and SXTsq 5ac. The signal is around -67dBm on both sides. The problem is I cannot achieve more than 30-35Mbps from server1 to pc1. Upload goes pretty well (about 92Mbps). TCP Bandwidth test between hAP_ax3 and LHG 5XL shows ~95Mbps in both directions. Similar results between LHG and SXTsq.
FTP throughput between LHG and SXTsq is around 90Mbps (both directions). Same results between LHG and server1 (or internet). I can’t understand why I’m limited to 30-35Mbps when packets are forwarded through LHG. CPU load is around 30% , latency 1-2ms. There are no queues on any device. No matter if LHG acts as bridge or router.
RoS 6.49.6 mipsbe.
Did anybody faced similar issue?
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