Deleted:FASTQC: Sample with wrong bases (A and G) matching in 'per base content' report

Question

[arctic]

Dear all, I am working on an archival dataset of Arabidopsis Thaliana. During running FASTQC, one of the samples shows a strange pattern of 'Per base sequence content'. In both forward and reverse sequences, A and G contents seem to match closely (instead of A and T, see the image below). In the attached image, S1 is the sample and Ex is an example of output from other samples.

I wonder if anyone has any experience with this pattern of base content and/or has any advice on how to go about troubleshooting/using the sample?

Thanks a lot in advance,