If you do not already have the following, try adding:
/etc/rc.local
echo "0" >> /sys/kernel/debug/ieee80211/phy0/mwlwifi/tx_amsdu && echo "0" >> /sys/kernel/debug/ieee80211/phy1/mwlwifi/tx_amsdu && logger "AMSDU Disabled"
If you do not already have the following, try adding:
echo "0" >> /sys/kernel/debug/ieee80211/phy0/mwlwifi/tx_amsdu && echo "0" >> /sys/kernel/debug/ieee80211/phy1/mwlwifi/tx_amsdu && logger "AMSDU Disabled"