I believe, that the reason why I have so many problems with achievement is that I have "Years" achievement. Try to have it and get any new achievement, I believe.
Reproduction rate (Every time? Sometimes?):
Every time I get completely new achievement (for example when I upgraded to silver Plunderer from bronze).
Browser and Version:
Chrome
Visual Reference if available (Screenshot) please put them in a spoiler.:
[spoil]
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Player name and market for rewards:
musaraj, Polish plemiona.pl