Some strokes convert to fills on EPS export - others do not

[Boldlinedesign 20]

I had someone trace a design with the pen tool in Affinity Designer and send me the file. I opened it in Affinity Designer and exported it as an EPS to import into Illustrator and found that some of the strokes (not all) had converted to fills in the process. I attached a sample of the design in Affinity (strokes) and when I opened it after exporting to EPS in Illy.
Am I better off exporting as an SVG? Am I missing something?

[Boldlinedesign 20]

Is there a sure-fire way to export a file created in Affinity Designer to preserve strokes and not convert them to fills when opened in another vector app like Illustrator? Thanks

 

[Boldlinedesign 20]

So this was resolved when I found another post about the same topic on the forum by GabrielM. thank you!

 

[GabrielM 602]

I'm glad you got it sorted!