Dyalog APL/S-64 Version 18.2.45405 -- dyalogscript reading inconsistently from /dev/stdin

session.sh

# let's read from /dev/stdin

$ cat some.apl
⍝⎕←⍴⊃⎕NGET 'zeros.txt'
⎕←⍴⊃⎕NGET '/dev/stdin'
$ dd if=/dev/zero count=1 bs=100000 | dyalogscript <(cat some.apl)
1+0 records in
1+0 records out
100000 bytes (100 kB, 98 KiB) copied, 0.0149497 s, 6.7 MB/s
100001

# notice above that dd finished and output to stderr and dyalogscript read in all the bytes.
# that is as expected -- 100000 + 1 newline character.

# but if we send in more bytes...

$ dd if=/dev/zero count=100 bs=100000 | dyalogscript <(cat some.apl)
100001
$ dd if=/dev/zero count=100 bs=100000 | dyalogscript <(cat some.apl)
130369

# notice above that dd doesn't finish and output to stderr and dyalogscript doesn't read in a consistent amount of bytes.

# but if we first write the bytes to a file and read from that file...

$ dd if=/dev/zero count=1000 bs=100000 > zeros.txt
1000+0 records in
1000+0 records out
100000000 bytes (100 MB, 95 MiB) copied, 0.259264 s, 386 MB/s
$ cat some.apl
⎕←⍴⊃⎕NGET 'zeros.txt'
⍝⎕←⍴⊃⎕NGET '/dev/stdin'
$ dyalogscript <(cat some.apl)
100000001
$ dyalogscript <(cat some.apl)
100000001

# then dyalogscript reads in all of the bytes consistently.

# why doesn't dyalogscript read all the bytes from /dev/stdin consistently?

session_19_0.sh

# inside a docker container running docker image dyalog/techpreview:19.0
#
dyalog@ecae2a813db9:/mnt$ cat some.apl 
⍝⎕←⍴⊃⎕NGET 'zeros.txt'
⎕←⍴⊃⎕NGET '/dev/stdin'
dyalog@ecae2a813db9:/mnt$ /opt/mdyalog/19.0/64/unicode/scriptbin/dyalogscript some.apl
Stream 3:  MOD: line : 1 can't open. "/"
dyalog@ecae2a813db9:/mnt$ /opt/mdyalog/19.0/64/unicode/scriptbin/dyalogscript <(cat some.apl)
script file "/dev/fd/63" could not be found