Strange triangular cutouts appearing on polygon pour

[worldwideglide]

I recently inherited an 8-layer PCB that is supposedly "ready for manufacturing". However when taking a look at the copper layers I notice something strange... On every layer there are these triangular cutouts on the polygon pour in seemingly random places. Each layer has them in different places and I don't see any correlation between them and other objects. This is one of the internal signal layers:



Re-pouring the existing polygon or changing the polygon properties or rules does not fix it. The only way I can get rid of these triangles is to delete the polygon pour and place a new (identical) polygon pour.

Any ideas on what would cause this?

*Edit: I'm having trouble uploading the image

[thm_w]

This is the gerber viewer right?
Does it show up like this inside Altium as well?

[Bud]

Probably version (in)compatibility. Try generating Gerbers and see if the issue gets transposed on Gerbers. If it does then i guess you need to regenerate the polys.

[worldwideglide]

This is the gerber viewer right?
Does it show up like this inside Altium as well?

Yes this is the gerber viewer. The issue shows up on both gerber and inside Altium.

[worldwideglide]

Probably version (in)compatibility. Try generating Gerbers and see if the issue gets transposed on Gerbers. If it does then i guess you need to regenerate the polys.

It does get transposed unfortunately. I'll just assume a compatibility issue and that this was not an intended design decision!

[ajb]

Are the existing polygons members of any classes?  You can check this in the object class explorer, Design > Classes.  Or does the behavior change if you rename one of the polygons? Polygon classes and names may be referenced in non-polygon rules that could affect polygon generation. 

What does the outline of the polygon look like? If you change it does the behavior change?

[VK3DRB]

Try saving as a different Gerber format.
 
Or a different Gerber viewer. For RS-274X Gerbers, I use as free Gerber viewer called GerbV as well as Altium. GerbV does an extra sanity check and can be easier to see stuff than Altium's Gerber viewer. It is pretty simple to use, but works fine.

There are other free Gerber viewers around, like ViewPlot, GerberLogix etc.

[thm_w]

Try saving as a different Gerber format.
 
Or a different Gerber viewer. For RS-274X Gerbers, I use as free Gerber viewer called GerbV as well as Altium. GerbV does an extra sanity check and can be easier to see stuff than Altium's Gerber viewer. It is pretty simple to use, but works fine.

There are other free Gerber viewers around, like ViewPlot, GerberLogix etc.

OP already said the issue is also in altium.