No problems here. Here are the pertinent bits of my configs:
/etc/config/network
config interface 'wgserver'
option proto 'wireguard'
option private_key '<redacted>'
option listen_port '52000'
list addresses '192.168.99.1/24'
config wireguard_wgserver
option public_key '<redacted>'
list allowed_ips '192.168.99.3/32'
option persistent_keepalive '25'
option description 'pixel'
/etc/config/firewall
config rule
option src '*'
option target 'ACCEPT'
option proto 'udp'
option dest_port '52000'
option name 'Allow-Wireguard-Inbound'
config zone
option name 'lan'
option input 'ACCEPT'
option output 'ACCEPT'
option forward 'ACCEPT'
option network 'lan wgserver'