What these messages are referring to when it says write error in Zoew 2.4.0 STC:
JSON: write error, rc -1, return code 0, reason code 00000000.
ZOWE 2.4.0
JSON: write error, rc -1, return code 0, reason code 00000000.
This message was shown by default in ZOWE version 2.4.0, it is related to debug mode turned on for Zowe launcher, and it should be disabled by default in Zowe 2.5.0