Headquarter A and B connect via IPsec lan to lan. And A as a L2TP/PPTP client to lan server. A client connects to headquarter A( L2TP/PPTP server), and then it could access 192.168.10.0/24. And now...

Eh..What a weird phenomenon! Have you updated into FW180117? Because they published it on 2/9 and I just updated my device two days ago.

Bandwidth Control could limit speed of specific IP address. And it works for me

TL-R470T+ v6 has the option of WAN_ALL. There are some emulators on their website. That's very helpful. I post it for you....

well, your company share-it only could be reached from WAN1, right? Do you configure any other Load Balance feature, like Link Backup or any other? Screenshots of all Load Balance configuration will...

Eh..the device hardware version is?.....Are WAN1 and WAN2 always up? If they are, you should configure Policy Routing. A FAQ on their official website may help. https://www.tp-link.com/en/faq-530.html