PPP changes reverting after reboot

Greeting,

I have a strange issue, I have a MikroTik RB751U-2HnD running RouterOS v5.21. I have two SSTP client connections created, connecting to different VPN servers. Recently, I had to change some details of one the connections. I made the changes easily enough through Winbox, however now when I reboot this router the SSTP client reverts back to its previous values.

Thanks in advance
shthco