qBittorrent official forums

This looks to be a confirmed problem in github. Do not torrent until you check your proxy settings. If they are grayed out, then just reset your settings, (I believe setting the proxy "Types" field will get it back on).

Yeah it's a known issue, devs are looking into it. I've had it happen too unfortunately.
Though, proxy is just proxy (not encrypted, no protection), I'd highly recommend using a VPN with interface binding (and killswitch maybe).

I believe unless the ISPs (or Internet backbone) ups their torrent monitoring game with deep analysis of torrent traffic, proxies are still safe? I believe it would require them to capture some torrent traffic and deencrypting the weak bittorrent encryption (I have the "require encryption" qbittorrent option on). This is a lot harder than just third party monitoring companies running monitoring torrent clients on the various popular torrents and grabbing IPs. I am hoping that if such ISP monitoring became even moderately widespread I would hear about it, VPN companies would shut down their torrent proxy services and the torrent clients would remove the proxy feature. Without a VPN, just to be more safe, I use Tor Browser when accessing torrent online indexes.