PCMSTREAM is completely broken

After a few seconds (depending on the sample rate), PCMSTREAM starts producing random noise, and sometimes randomly changes speed. 32730 seems to work forever, and 8180, 16360, etc. work for a few minutes. Values far from these will quickly break. https://www.dropbox.com/s/cij46k8ib2ps79t/bad.mp3?dl=0 (skip to 0:27) Another example (all crackling and speed inconsistencies caused by PCMSTREAM) https://www.dropbox.com/s/hxcbi0gt7qmfjc9/test3.mp3?dl=0 and some code:

DIM P[10000]
FILL P,32767
FOR I=0 TO LEN(P)-1
 IF I MOD 200<100 THEN P[I]=-32767
NEXT
PCMSTREAM P,44100
WHILE 1:WEND