[Known Issue] Build uploads failing

Currently trying to upload a build using the ovr platform tool, and it is failing every time. It tries "Fetching previous build" and then "reconstructing uploaded file" 4 times and then fails with "ERROR: Sorry, we encountered a problem while processing the file that you uploaded. Please try again later."

I'm trying to upload to the ALPHA channel, and we do have a build in the store channel that passed it's tests last night. Other than that, can't see what the issue would be. Log excerpt:

2018-12-14T16:47:51.902Z [DEBUG] 
Preparing for upload...
2018-12-14T16:47:52.234Z [DEBUG] 
Uploading OBB...
2018-12-14T16:47:52.235Z [DEBUG] 
Downloading signature of previous build
2018-12-14T16:47:53.122Z [DEBUG] 
Generating patch
2018-12-14T16:48:55.521Z [DEBUG] 
Uploading...
2018-12-14T16:48:55.520Z [DEBUG] Started upload: 555568911555278
2018-12-14T16:49:08.269Z [DEBUG] 
Waiting for processing to begin...
2018-12-14T16:49:09.673Z [DEBUG] 
fetching previous build (2 / 4)
2018-12-14T16:49:21.973Z [DEBUG] 
reconstructing uploaded file (1 / 4)
2018-12-14T16:49:23.201Z [DEBUG] 
fetching previous build (2 / 4)
2018-12-14T16:49:43.055Z [DEBUG] 
reconstructing uploaded file (1 / 4)
2018-12-14T16:49:44.201Z [DEBUG] 
fetching previous build (2 / 4)
2018-12-14T16:50:26.079Z [DEBUG] 
reconstructing uploaded file (1 / 4)
2018-12-14T16:50:27.319Z [DEBUG] 
fetching previous build (2 / 4)
2018-12-14T16:51:46.584Z [DEBUG] 
reconstructing uploaded file (1 / 4)
2018-12-14T16:51:47.824Z [DEBUG] 
fetching previous build (2 / 4)
2018-12-14T16:54:28.367Z [DEBUG] 

ERROR: Sorry, we encountered a problem while processing the file that you uploaded. Please try again later.

2018-12-14T16:54:28.368Z [WARN] Server log: {"app_id":****,"log_level":"WARN","event_name":"USER_ERROR","stack_trace":"UserVisibleError: Sorry, we encountered a problem while processing the file that you uploaded. Please try again later.\n\n    at [eval]:34:36\n    at [eval]:66:5252\n    at next (native)\n    at a ([eval]:66:1010)\n    at [eval]:66:1104\n    at process._tickCallback (internal/process/next_tick.js:103:7)","extra":"{\"os\":\"{\\\"platform\\\":\\\"win32\\\",\\\"arch\\\":\\\"ia32\\\",\\\"type\\\":\\\"Windows_NT\\\"}\",\"cli_version\":\"1.25.0.694215\",\"compatibility_version\":2,\"app_id\":****,\"platform\":\"ANDROID\",\"session_id\":\"****_2018-12-14T16:47:51.871Z\",\"isObb\":true,\"chunked_upload_id\":\"555568911555278\"}"}