"muxavformat: avformat_write_header failed!" - why?

I'm backing up a DVD using handbrake 0.10.2 (x86_64) on Linux Mint 18.2. With 1-pass encoding - it works, but with 2-pass encoding, I get the following:

[15:44:44] starting job
[15:44:44] sync: expecting 165614 video frames
[15:44:44] job configuration:
[15:44:44]  * source
[15:44:44]    + /media/joeuser/MYDVD/VIDEO_TS
[15:44:44]    + title 1, chapter(s) 1 to 1
[15:44:44]  * destination
[15:44:44]    + /tmp/out.mkv
[15:44:44]    + container: Matroska (libavformat)
[15:44:44]  * video track
[15:44:44]    + decoder: mpeg2video
[15:44:44]      + bitrate 200 kbps
[15:44:44]    + filters
[15:44:44]      + Detelecine (pullup) (default settings)
[15:44:44]      + Framerate Shaper (0:27000000:900900)
[15:44:44]        + frame rate: same as source (around 29,970 fps)
[15:44:44]      + Crop and Scale (682:348:28:104:22:16)
[15:44:44]        + source: 720 * 480, crop (28/104/22/16): 682 * 348, scale: 682 * 348
[15:44:44]    + loose anamorphic
[15:44:44]      + storage dimensions: 682 * 348, mod 2
[15:44:44]      + pixel aspect ratio: 8 / 9
[15:44:44]      + display dimensions: 606 * 348
[15:44:44]    + encoder: H.264 (libx264)
[15:44:44]      + preset:  slower
[15:44:44]      + tune:    film
[15:44:44]      + profile: main
[15:44:44]      + level:   4.0
[15:44:44]      + bitrate: 2500 kbps, pass: 2
[15:44:44]  * subtitle track 1, English (track 1, id 0x20bd) Picture [VOBSUB] -> Passthrough, Forced Only, Default
[15:44:44]  * subtitle track 2, Closed Captions (track 0, id 0x0) Text [CC] -> Passthrough
[15:44:44]  * audio track 1
[15:44:44]    + decoder: English (AC3) (2.0 ch) (track 1, id 0x80bd)
[15:44:44]      + bitrate: 192 kbps, samplerate: 48000 Hz
[15:44:44]    + mixdown: Stereo
[15:44:44]    + encoder: AAC (libavcodec)
[15:44:44]      + bitrate: 160 kbps, samplerate: 48000 Hz
[15:44:44]  * audio track 2
[15:44:44]    + decoder: Espanol (AC3) (2.0 ch) (track 2, id 0x81bd)
[15:44:44]      + bitrate: 192 kbps, samplerate: 48000 Hz
[15:44:44]    + mixdown: Stereo
[15:44:44]    + encoder: AAC (libavcodec)
[15:44:44]      + bitrate: 160 kbps, samplerate: 48000 Hz
libdvdnav: Using dvdnav version 5.0.3
libdvdread: Attempting to use device /dev/sr0 mounted on /media/eyalroz/CHIAPAS for CSS authentication
libdvdnav: Can't read name block. Probably not a DVD-ROM device.
libdvdnav: vm: dvd_read_name failed
libdvdnav: DVD disk reports itself with Region mask 0x00000000. Regions: 1 2 3 4 5 6 7 8
libdvdread: Attempting to use device /dev/sr0 mounted on /media/joeuser/MYDVD for CSS authentication
libdvdnav: DVD disk reports itself with Region mask 0x00000000. Regions: 1 2 3 4 5 6 7 8
[15:44:44] encx264: min-keyint: 30, keyint: 300
[15:44:44] encx264: encoding at average bitrate 2500

libdvdread: Attempting to retrieve all CSS keys
libdvdread: This can take a _long_ time, please be patient

libdvdread: Get key for /VIDEO_TS/VTS_01_0.VOB at 0x0000010c
libdvdread: Elapsed time 0
libdvdread: Get key for /VIDEO_TS/VTS_01_1.VOB at 0x0000013a
libdvdread: Elapsed time 0
libdvdread: Found 1 VTS's
libdvdread: Elapsed time 0
[15:44:44] encx264: unparsed options: level=4.0:ref=8:b-adapt=2:direct=auto:deblock=-1,-1:analyse=all:8x8dct=0:me=umh:subme=9:trellis=2:psy-rd=1,00,0,15:vbv-bufsize=25000:vbv-maxrate=20000:rc-lookahead=60
[15:44:44] reader: first SCR 146 id 0xe0 DTS 22254
x264 [info]: using SAR=8/9
x264 [info]: using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
[15:44:44] mpeg2video: "Chapter 1" (1) at frame 0 time 3003
x264 [info]: profile Main, level 4.0
[15:44:46] sync: first pts is 3003
[15:44:46] muxavformat: avformat_write_header failed!
[15:44:46] reader: done. 1 scr changes
[15:44:46] work: average encoding speed for job is 0,000000 fps
[15:44:47] sync: got 35 frames, 165614 expected
[15:44:47] render: lost time: 9009 (0 frames)
[15:44:47] render: gained time: 9009 (4 frames) (0 not accounted for)
[15:44:47] mpeg2video-decoder done: 45 frames, 0 decoder errors, 0 drops
[15:44:47] ac3-decoder done: 0 frames, 0 decoder errors, 0 drops
[15:44:47] ac3-decoder done: 0 frames, 0 decoder errors, 0 drops
[15:44:47] mux: track 0, 0 frames, 0 bytes, 0,00 kbps, fifo 8
[15:44:47] mux: track 1, 0 frames, 0 bytes, 0,00 kbps, fifo 8
[15:44:47] mux: track 2, 0 frames, 0 bytes, 0,00 kbps, fifo 8
[15:44:47] mux: track 3, 0 frames, 0 bytes, 0,00 kbps, fifo 8
[15:44:47] mux: track 4, 0 frames, 0 bytes, 0,00 kbps, fifo 8
[15:44:47] libhb: work result = 3

What's wrong? I don't get it.