Ghost ? peaks on GS Oxyplot column

We recently purchased a GS Oxyplot column based on its reported excellence for separating oxygenated compounds in hydrocarbons streams such as Ethylene, which is required to be of ultra high purity for polymerization catalysts. Unfortunately we see a multitude of peaks in the chromatogram that are clearly not coming from the ethylene sample ( as we get the same peaks in a multitude of samples from different sources.)   Our GC only has an FID detector so we do not know what the identity of the peaks are, but are certain they are not coming from the sample. Scan below used a temperature program of  4mins at 60C ramped to 200 C at 10 C/min and hold at 200 for 12 min. He carrier gas and 1 ml vapour sample ( with split injection )

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