Interesting - the proc-pid-parser actually parses that file name just fine:

    $ echo '2001 (bad) S 1 2 3 4 5) S 1888 2001 1888 34816 2001 4202496 428 0 0 0 0 0 0 0 20 0 1 0 75513 115900416 297 18446744073709551615 4194304 5100612 140737020052256 140737020050904 140096699233308 0 65536 4 65538 18446744072034584486 0 0 17 0 0 0 0 0 0 7200240 7236240 35389440 140737020057179 140737020057223 140737020057223 140737020059606 0' | jc --proc-pid-stat

    {"pid":2001,"comm":"bad) S 1 2 3 4 5","state":"S","ppid":1888,"pgrp":2001,"session":1888,"tty_nr":34816,"tpg_id":2001,"flags":4202496,"minflt":428,"cminflt":0,"majflt":0,"cmajflt":0,"utime":0,"stime":0,"cutime":0,"cstime":0,"priority":20,"nice":0,"num_threads":1,"itrealvalue":0,"starttime":75513,"vsize":115900416,"rss":297,"rsslim":18446744073709551615,"startcode":4194304,"endcode":5100612,"startstack":140737020052256,"kstkeep":140737020050904,"kstkeip":140096699233308,"signal":0,"blocked":65536,"sigignore":4,"sigcatch":65538,"wchan":18446744072034584486,"nswap":0,"cnswap":0,"exit_signal":17,"processor":0,"rt_priority":0,"policy":0,"delayacct_blkio_ticks":0,"guest_time":0,"cguest_time":0,"start_data":7200240,"end_data":7236240,"start_brk":35389440,"arg_start":140737020057179,"arg_end":140737020057223,"env_start":140737020057223,"env_end":140737020059606,"exit_code":0,"state_pretty":"Sleeping in an interruptible wait"}

But the "magic" signature doesn't recognize it:

    $ echo '2001 (bad) S 1 2 3 4 5) S 1888 2001 1888 34816 2001 4202496 428 0 0 0 0 0 0 0 20 0 1 0 75513 115900416 297 18446744073709551615 4194304 5100612 140737020052256 140737020050904 140096699233308 0 65536 4 65538 18446744072034584486 0 0 17 0 0 0 0 0 0 7200240 7236240 35389440 140737020057179 140737020057223 140737020057223 140737020059606 0' | jc --proc             
    jc:  Error - Parser issue with proc:
                 ParseError: Proc file could not be identified.
                 ...

I can fix the "magic" signature (regex) to look for more parts of the stat file.