Barcode attribute is not good enough, causes characterization problem and result to print quality issue.
There are two 1D barcodes printed on this document, both created using the same font, containing numeric info only but one is at 14 point in size, the other is 5 point in height.
The barcode scanner is not able to read the 5 point barcode, even the print looks acceptable.
According to engineering, the target printer is not able to print the 5 point size barcode with enough detail, for the scanner to be able to read it accurately.
The 5 point barcode is adjusted to be in larger size as recommended, and this resolved the issue. This recommendation is base on Barcode Standards, which is specified in this link
UPDATED: October 01, 2018