ffmpeg Large-file error?

[Dexter N Muir]

Winff 1.5.5 on Kubuntu 17.04, hp p6-2175a (i3), which uses ffmpeg 
7:3.2.4-1build2 (this time, though historical):

ffmpeg 1st pass window:
/usr/bin/ffmpeg -y -i "/drv2/My 
Videos/_aMule/Incoming/Formula.One.17.United.States.Grand.Prix.720p.HDTV.x264-VERUM.[tvu.org.ru].mkv" 
-crf 23.0 -vcodec libx264 -filter:v scale=w=720:h=406 -preset slow 
-acodec aac -strict experimental -ar 48000 -b:a 128k -coder 1 -flags 
+loop -cmp chroma -partitions +parti4x4+partp8x8+partb8x8 -me_method hex 
-subq 6 -me_range 16 -g 250 -keyint_min 25 -sc_threshold 40 -i_qfactor 
0.71 -b_strategy 1 -threads 0 
"/drv2/Formula.One.17.United.States.Grand.Prix.HDTV.x264-VERUM.[tvu.org.ru].mp4"

Error message in Konsole, Kubuntu's Terminal:
[ac3 @ 0x563f33722b60] exponent 25 is out-of-range1:01:02.99 
bitrate=1447.7kbits/s dup=53 drop=0 speed=1.36x
[ac3 @ 0x563f33722b60] error decoding the audio block
frame=207544 fps= 62 q=-1.0 Lsize=  744330kB time=01:09:11.09 
bitrate=1468.9kbits/s dup=73 drop=0 speed=1.25x

The error message is actually the two "ac3 @" lines, the first ([ac3 @ 
0x563f33722b60] exponent 25 is out-of-range) overwrites the underlying 
progress line (which gives the point at which the error occurs, 1 hour, 
consistently), and is probably the important one.
That last line, (frame ... 1.25x) is ongoing progress.
(Incidentally, the progress line is padded out to beyond Konsole's 
default width, resulting in screensful of progress lines until widening 
the view, at which point it overwrites itself)
The error seems to be non-fatal; the process continues to completion and 
the result seems to be unaffected.

Hopefully enough to work on ...

Cheers
Dex