We found out that there is a text field on b.cu at a very odd position.
(y coordinate = -2147.483648)
The problem seems to be that this gets internally converted to a 32 bit signed integer with value -2147483648 = 0x80000000 which is the smallest value re-presentable in this number format.
The problem happens when the gerber exporter tries to create the upper half of the text field. (the one pointed more in y minus direction)
Because this numbers can not be represented in the 32 bit integer used, the text wraps around and continues at the maximum positive value representable.
(which results in 4 meter long lines in the gerber.)
after your last input i tested the export of a 4.5 gerber. This gerber seems to remove the half of the text that creates the overflow. The text is still there at this ludicrous y position.
The main question now is: Where does this value come from?
I doubt that it was done by the user himself. (It is exactly the minimum re-presentable value.)
So i fear some tool moved the text to this position. The question is what tool is responsible.
And of course: Can we find a way to reproduce this reliably such that we can give the developers a good bug report?
(There are two bugs here. One bug is the integer overflow, the other is the tool that moved the text.)