I purhcased my spark a few days ago and have been enjoying flying it inside with the prop guards installed from the fly more combo for a few days now. However, I am running into an occasional issue that is making the drone slightly unpredictable.
First off, let me give you my setup:

• DJI Spark Drone
• Spark RC
• Samsung Galaxy S8 (Android 7.0) Connected via Wifi to Controller
• Drone Firmware Version - 01.00.0800
• RC Firmware Version - 01.000.0400
• DJI Go 4 App Version - 4.1.15 (Downgraded)
  

As far as I can tell the drone flies just fine as long as it remains in ATTI or VPS mode. The issue is when it does catch a glimpse of GPS mode it tosses it out of whatever fly mode I am currently in and back to normal. For example, if I am flying around my house with tripod mode turned on, if GPS is acquired during flight, it will go from tripod mode to normal mode automatically and if I happen to be slowing moving towards an object in tripod mode it will rapidly begin to accelerate towards said object.

The drone has been phenomental otherwise, but I wanted to see what others thought. Here are the logs as well:
http://www.phantomhelp.com/LogViewer/V7ZRS07CQJTHQQR3CFGV/

Hi, sir. Did you crash your drone before? Please try to use the latest version of app. If the problem remains, please shoot a video about this situation and provide the flight data, black box data.

Have you got obstacle avoidance on ?

Also make the room as bright as possible so the VPS can work and use prop guards.

lannes Posted at 2017-12-20 19:40
Have you got obstacle avoidance on ?

Also make the room as bright as possible so the VPS can work and use prop guards.

Thank you! Low light is likely exactly what caused the VPS system to stop working. I was flying into a room without the lights on (they're triggered by motion but the DJI Spark is too small to trigger it on its own).

Looking at the logs it seems this is exactly what happened too, with the drone going from VPS to ATTI again as I moved into the dark room. Glad to hear this is completely normal behavior and I'll keep an eye out on it in the future.

However, if I could make a recommendation, the software should absolutely warn the user with some audible type of tone as it moves between modes.

asourceunknown Posted at 2017-12-20 21:39
Thank you! Low light is likely exactly what caused the VPS system to stop working. I was flying into a room without the lights on (they're triggered by motion but the DJI Spark is too small to trigger it on its own).

Looking at the logs it seems this is exactly what happened too, with the drone going from VPS to ATTI again as I moved into the dark room. Glad to hear this is completely normal behavior and I'll keep an eye out on it in the future.

It  does , it screams out "Atti mode", your volume must be too low

lannes Posted at 2017-12-20 21:53
It  does , it screams out "Atti mode", your volume must be too low

Right you are. *Diligently goes to reading the manual*

I also have experienced that tripod mode is risky indoor.
By using sport mode, I’m sure it won’t suddenly speed up if it goes to gps or atti mode..

asourceunknown Posted at 2017-12-20 21:39
Thank you! Low light is likely exactly what caused the VPS system to stop working. I was flying into a room without the lights on (they're triggered by motion but the DJI Spark is too small to trigger it on its own).

Looking at the logs it seems this is exactly what happened too, with the drone going from VPS to ATTI again as I moved into the dark room. Glad to hear this is completely normal behavior and I'll keep an eye out on it in the future.

Glad you find the reason. Your recommendation will be forwarded. Thanks for your feedback.