SUWIND sets wrong delrt when tmin is supplied

[speleos]

This has been reproduced in both 44R28 and 44R19.

channelcut.su is my original file, 600 seconds long, an excerpt from a DAS recording.

surange < channelcut.su
51 traces:
tracl 3800 3850 (3800 - 3850)
tracr 3800 3850 (3800 - 3850)
fldr 1
tracf 1
ep 1000
offset 38040 38540 (38040 - 38540)
gx 38040 38540 (38040 - 38540)
ns 27000
dt 20000

If I cut it at tmax, I obtain the following:

suwind < channelcut.su tmax=500 | surange
51 traces:
tracl 3800 3850 (3800 - 3850)
tracr 3800 3850 (3800 - 3850)
fldr 1
tracf 1
ep 1000
offset 38040 38540 (38040 - 38540)
gx 38040 38540 (38040 - 38540)
ns 25001
dt 20000

However, if I cut it at tmin, delrt is set to a number that I can't understand.

suwind < channelcut.su tmin=100 | surange51 traces:
tracl 3800 3850 (3800 - 3850)
tracr 3800 3850 (3800 - 3850)
fldr 1
tracf 1
ep 1000
offset 38040 38540 (38040 - 38540)
gx 38040 38540 (38040 - 38540)
delrt -31072
ns 22000
dt 20000

If other tmin values are used, delrt changes too.
suwind < channelcut.su tmin=300 tmax=500 | surange
51 traces:
tracl 3800 3850 (3800 - 3850)
tracr 3800 3850 (3800 - 3850)
fldr 1
tracf 1
ep 1000
offset 38040 38540 (38040 - 38540)
gx 38040 38540 (38040 - 38540)
delrt -27680
ns 10001
dt 20000

I've attached the file to reproduce the issue.

channelcut.su.zip