I am experiencing the same behavior on a FreeBSD 11.3 system
PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND
485 root 1 103 0 6296K 2124K CPU1 1 67:33 98.93% tr
167 root 1 102 0 6296K 2124K CPU3 3 24:57 95.39% tr
root@srv2a:/usr/local/directadmin/custombuild # lsof -p 167
lsof: WARNING: compiled for FreeBSD release 11.3-RELEASE-p5; this is 11.3-RELEASE-p3.
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
tr 167 root cwd VDIR 0,61 3072 324928 /usr/local/directadmin/custombuild
tr 167 root rtd VDIR 0,61 1024 2 /
tr 167 root 0r VCHR 0,4 0x5ebd55000 4 /dev/random
tr 167 root 1u PIPE 0xfffff8000a3ed168 0 ->0xfffff8000a3ed000
tr 167 root 2w VCHR 0,28 0t0 28 /dev/null
root@srv2a:/usr/local/directadmin/custombuild # lsof -p 485
lsof: WARNING: compiled for FreeBSD release 11.3-RELEASE-p5; this is 11.3-RELEASE-p3.
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
tr 485 root cwd VDIR 0,61 3072 324928 /usr/local/directadmin/custombuild
tr 485 root rtd VDIR 0,61 1024 2 /
tr 485 root 0r VCHR 0,4 0xf242e7000 4 /dev/random
tr 485 root 1u PIPE 0xfffff800a934ed48 0 ->0xfffff800a934ebe0
tr 485 root 2w VCHR 0,28 0t0 28 /dev/null
tr 485 root 3u PIPE 0xfffff801125072f8 16384 ->0xfffff80112507460
tr 485 root 6u PIPE 0xfffff800ea476758 0 ->0xfffff800ea4765f0
edit: i completely removed custombuild and reinstalled it, saving only the options.conf. it seems to have resolved it but i'm going to monitor