It could be a false positive. You can extract the file carefully from Chest and submit it to www.virustotal.com to check.
Anyway, there is no rush to delete a file from Chest. It’s safe there.
First, no security program have 100% detection
It could also be a file MBAM/SAS is not looking fore…dont think this is, as it is a trojan
MBAM also only want fresh malware not older then 3months
So what is the name of the file detected and where was it located…full path