Soundpool Frequently Showing Significant Latency And Issuing "deep-buffer-playback" Message

I am testing Soundpool on a Moto-E running 5.1. It often starts with excellent latency - but then the audio begins hanging for a hundred milliseconds or more with the following message:

06-26 15:03:49.213 3865-9536/? E/DEBUG MESSAGE: Play Note BEFORE

06-26 15:03:49.331 299-876/? D/audio_hw_primary: out_set_parameters: enter: usecase(0: deep-buffer-playback) kvpairs: routing=8

06-26 15:03:49.331 299-876/? V/msm8916_platform: platform_get_output_snd_device: enter: output devices(0x8)

06-26 15:03:49.331 299-876/? V/msm8916_platform: platform_get_output_snd_device: exit: snd_device(headphones)

06-26 15:03:49.331 299-876/? D/audio_hw_extn: audio_extn_set_anc_parameters: anc_enabled:0

06-26 15:03:49.331 299-876/? E/soundtrigger: audio_extn_sound_trigger_set_parameters: str_params NULL

06-26 15:03:49.334 3865-9536/? E/DEBUG MESSAGE: Play Note AFTER

The DEBUG messages are mine. The others are system generated. Notice I am losing over 100ms. I checked my sample rate and it is good. It also doesn't happen for every note. May I ask if anyone is familiar with this type of error?