Hello,
PIWIK: 3.2.1
QueuesTracking: 3.1.0

During import json files from Apache (when above plugins is enabled), there is an error:
2017-12-07 08:13:09,741: [INFO] bulk tracking returned invalid JSON 2017-12-07 08:13:09,741: [INFO] tracker response: GIF89a�!�,D; 2017-12-07 08:13:09,872: [INFO] bulk tracking returned invalid JSON 2017-12-07 08:13:09,872: [INFO] tracker response: GIF89a�!�,D; 2017-12-07 08:13:09,956: [INFO] bulk tracking returned invalid JSON 2017-12-07 08:13:09,956: [INFO] tracker response: GIF89a�!�,D; 2017-12-07 08:13:10,093: [INFO] bulk tracking returned invalid JSON 2017-12-07 08:13:10,093: [INFO] tracker response: GIF89a�!�,D; 2017-12-07 08:13:10,180: [INFO] bulk tracking returned invalid JSON 2017-12-07 08:13:10,180: [INFO] tracker response: GIF89a�!�,D; 2017-12-07 08:13:10,263: [INFO] bulk tracking returned invalid JSON 2017-12-07 08:13:10,263: [INFO] tracker response: GIF89a�!�,D; 2017-12-07 08:13:10,403: [INFO] bulk tracking returned invalid JSON 2017-12-07 08:13:10,403: [INFO] tracker response: GIF89a�!�,D; 2017-12-07 08:13:10,537: [INFO] bulk tracking returned invalid JSON 2017-12-07 08:13:10,538: [INFO] tracker response: GIF89a�!�,D; 2017-12-07 08:13:10,668: [INFO] bulk tracking returned invalid JSON 2017-12-07 08:13:10,668: [INFO] tracker response: GIF89a�!�,D; 2017-12-07 08:13:10,753: [INFO] bulk tracking returned invalid JSON

OS Centos 7 (on both systems).