#79 optipng 0.7.6-0.7.7 cannot handle about 1000 chunks

[robpats]

sample.png has 1011 chunks.
After optimizing, result.png has 1004 chunks.
2 IDAT chunks are merged.
5 valid chunks are wrongly removed.

optipng-0.7.7-win32\optipng.exe -v -o3 -fix -out result.png sample.png
OptiPNG version 0.7.7
Copyright (C) 2001-2017 Cosmin Truta and the Contributing Authors.

** Processing: sample.png
Warning: tEXt: no space in chunk cache
300x150 pixels, 2 bits/pixel, 4 colors (4 transparent) in palette
Reducing image to 2 bits/pixel, 4 colors (3 transparent) in palette
Recoverable errors found in input. Fixing...
Input IDAT size = 890 bytes
Input file size = 56612 bytes

Trying:
zc = 9 zm = 9 zs = 0 f = 0 IDAT size = 865
zc = 9 zm = 8 zs = 0 f = 0 IDAT size = 865
zc = 9 zm = 9 zs = 1 f = 0 IDAT too big
zc = 9 zm = 8 zs = 1 f = 0 IDAT too big
zc = 1 zm = 9 zs = 2 f = 0 IDAT too big
zc = 1 zm = 8 zs = 2 f = 0 IDAT too big
zc = 9 zm = 9 zs = 3 f = 0 IDAT too big
zc = 9 zm = 8 zs = 3 f = 0 IDAT too big
zc = 9 zm = 9 zs = 0 f = 5 IDAT too big
zc = 9 zm = 8 zs = 0 f = 5 IDAT too big
zc = 9 zm = 9 zs = 1 f = 5 IDAT too big
zc = 9 zm = 8 zs = 1 f = 5 IDAT too big
zc = 1 zm = 9 zs = 2 f = 5 IDAT too big
zc = 1 zm = 8 zs = 2 f = 5 IDAT too big
zc = 9 zm = 9 zs = 3 f = 5 IDAT too big
zc = 9 zm = 8 zs = 3 f = 5 IDAT too big

Selecting parameters:
zc = 9 zm = 8 zs = 0 f = 0 IDAT size = 865

Output file: result.png

Output IDAT size = 865 bytes (25 bytes decrease)
Output file size = 56363 bytes (249 bytes = 0.44% decrease)

** Status report
1 file(s) have been processed.
1 error(s) have been encountered.
1 erroneous file(s) have been fixed.