Detchar safety injections took a few sec too long to initialize

I ran the DetChar safety injections, and it took a few seconds too long to initialize, and I got an error about the block time being past. I ran them a second time, and they worked just fine.

Details from the time it did not work:

ifo: H1
waveform root: /ligo/groups/cal/H1/hwinj
config file: /ligo/groups/cal/H1/hwinj/hwinj.yaml
GraceDB url: https://gracedb-playground.ligo.org/api/
GraceDB group: Test
GraceDB pipeline: HardwareInjection
excitation channel: H1:CAL-INJ_TRANSIENT_EXC
injection group: detchar
injection name: safety
injection waveform file: /ligo/groups/cal/H1/hwinj/detchar/detchar-hwinj-schedule_LIGO-T1900555-PROPOSED_H1_INJECTIONS.txt
injection waveform sample rate: 16384
injection log file: /ligo/groups/cal/H1/hwinj/detchar/detchar-hwinj-schedule_LIGO-T1900555-PROPOSED_H1_INJECTIONS_log.csv
injection start GPS: 1371831685.74
reading waveform file...
waveform length: 390.0 seconds
reading log file...
initiating ligo_proxy_init for GraceDB access...
H1:CAL-INJ_TINJ_TYPE => 3
H1:CAL-INJ_TINJ_TYPE => 3
H1:CAL-INJ_TRANSIENT_SW2 => 1024
H1:CAL-INJ_TRANSIENT_SW2 => 1024
H1::CAL-INJ_TRANSIENT => ON: OUTPUT
H1::CAL-INJ_TRANSIENT => ON: OUTPUT
=== EXECUTING AWG INJECTION ===
this will wait until the injection is nearly complete...
ndshosts: h1daqnds1 and h1daqnds0
getting host by name: h1daqnds1
found host
testpoint_client 1.0.0
found version 4 or newer test point interface
Traceback (most recent call last):
  File "/ligo/groups/cal/src/hwinj/hardware_injections.py", line 303, in <module>
    main()
  File "/ligo/groups/cal/src/hwinj/hardware_injections.py", line 258, in main
    stream.send(waveform)
  File "/var/opt/conda/base/envs/cds/lib/python3.9/site-packages/awg.py", line 633, in send
    self.append(data, scale=scale)
  File "/var/opt/conda/base/envs/cds/lib/python3.9/site-packages/awg.py", line 618, in append
    raise AWGStreamError("couldn't stream data to " + self.chan + \
awg.AWGStreamError: couldn't stream data to H1:CAL-INJ_TRANSIENT_EXC: Block time is already past (-3)

Then, immediately afterwards, details from the time it did work:

ifo: H1
waveform root: /ligo/groups/cal/H1/hwinj
config file: /ligo/groups/cal/H1/hwinj/hwinj.yaml
GraceDB url: https://gracedb-playground.ligo.org/api/
GraceDB group: Test
GraceDB pipeline: HardwareInjection
excitation channel: H1:CAL-INJ_TRANSIENT_EXC
injection group: detchar
injection name: safety
injection waveform file: /ligo/groups/cal/H1/hwinj/detchar/detchar-hwinj-schedule_LIGO-T1900555-PROPOSED_H1_INJECTIONS.txt
injection waveform sample rate: 16384
injection log file: /ligo/groups/cal/H1/hwinj/detchar/detchar-hwinj-schedule_LIGO-T1900555-PROPOSED_H1_INJECTIONS_log.csv
injection start GPS: 1371831707.24
reading waveform file...
waveform length: 390.0 seconds
reading log file...
initiating ligo_proxy_init for GraceDB access...
H1::CAL-INJ_TRANSIENT => ON: OUTPUT
H1::CAL-INJ_TRANSIENT => ON: OUTPUT
=== EXECUTING AWG INJECTION ===
this will wait until the injection is nearly complete...
ndshosts: h1daqnds1 and h1daqnds0
getting host by name: h1daqnds1
found host
testpoint_client 1.0.0
found version 4 or newer test point interface
H1:CAL-INJ_TRANSIENT_SW2 => 1024
H1:CAL-INJ_TRANSIENT_SW2 => 1024
H1::CAL-INJ_TRANSIENT => OFF: OUTPUT
H1::CAL-INJ_TRANSIENT => OFF: OUTPUT
H1:CAL-INJ_TINJ_TYPE => 0
H1:CAL-INJ_TINJ_TYPE => 0
=== INJECTION COMPLETE ===
creating injection events in GraceDB...