[warn] Socks version -125 not recognized.
I spotted version 0.3.1.8 consuming 100% CPU in idle state, and printing a lot of these messages on FreeBSD 11.1:
Nov 01 17:52:43.000 [warn] Socks version -125 not recognized. (Tor is not an http proxy.)
Nov 01 17:52:44.000 [warn] Socks version -125 not recognized. (Tor is not an http proxy.)
Nov 01 17:52:45.000 [warn] Socks version -125 not recognized. (Tor is not an http proxy.)
Nov 01 17:52:52.000 [warn] microdesc_cache_clean: Bug: Microdescriptor seemed very old (last listed 168 hours ago vs 168 hour cutoff), but is still marked as being held by 1 node(s). I found 1 node(s) holding it. Current networkstatus is 16 hours old. Hashtable badness is 0. (on Tor 0.3.1.8 ad5027f7dc790624)
Nov 01 17:52:52.000 [warn] microdesc_cache_clean: Bug: [0]: ID=8FCA94A1BEFA3F6E9524280528D43C1F8058327B. md=0x3073520, rs=0x428b0b0, ri=0x0. Microdesc digest in RS matches. RS okay in networkstatus. (on Tor 0.3.1.8 ad5027f7dc790624)
Nov 01 17:52:52.000 [warn] microdesc_cache_clean: Bug: Microdescriptor seemed very old (last listed 168 hours ago vs 168 hour cutoff), but is still marked as being held by 1 node(s). I found 1 node(s) holding it. Current networkstatus is 16 hours old. Hashtable badness is 0. (on Tor 0.3.1.8 ad5027f7dc790624)
Nov 01 17:52:52.000 [warn] microdesc_cache_clean: Bug: [0]: ID=A6AB9CCA65C4EAF7E9CD5EB8C53BEB77CF4743B9. md=0x2b9b9a0, rs=0x43fc550, ri=0x0. Microdesc digest in RS matches. RS okay in networkstatus. (on Tor 0.3.1.8 ad5027f7dc790624)
Nov 01 17:53:31.000 [warn] Socks version -125 not recognized. (Tor is not an http proxy.)
Nov 01 17:53:31.000 [warn] Socks version -125 not recognized. (Tor is not an http proxy.)
Nov 01 17:53:32.000 [warn] Socks version -125 not recognized. (Tor is not an http proxy.)
Nov 01 17:53:33.000 [warn] Socks version -125 not recognized. (Tor is not an http proxy.)
Nov 01 17:55:16.000 [warn] Socks version -125 not recognized. (Tor is not an http proxy.)
Nov 01 17:55:17.000 [warn] Socks version -125 not recognized. (Tor is not an http proxy.)
Nov 01 17:55:24.000 [notice] We'd like to launch a circuit to handle a connection, but we already have 32 general-purpose client circuits pending. Waiting until some finish. [1005770 similar message(s) suppressed in last 600 seconds]
Nov 01 17:56:11.000 [warn] Socks version -125 not recognized. (Tor is not an http proxy.)
Nov 01 17:56:27.000 [warn] Socks version -125 not recognized. (Tor is not an http proxy.)
Nov 01 17:58:02.000 [warn] Socks version -125 not recognized. (Tor is not an http proxy.)
Nov 01 17:58:04.000 [warn] Socks version -125 not recognized. (Tor is not an http proxy.)