unfortunately, it's still the same.
EDIT: So with some tinkering and multiple publishing I managed to remove the lines, bad news is I am not sure what helped exactly. Here is a list of things I changed that I can remember:
1. Shin's suggestion (Disabled accelerated graphics).
2. Format of Columns Pill (Year-Month) - Changed Shading color to background color
3. Enabled and disabled Drop Lines on Y-axis
EDIT2: After publishing new version of workbook the problem is again visible and I can't fix it. Little bit frustrating. I suspect the drop lines being issue but so fat no luck in nailing it.
Gonna drop a "me too" in here. I'm having the exact same problem. The lines do not show in desktop but do when published to server and viewed in a browser. I've tried different browsers, different machines, after turning off hardware acceleration, and on versions 10.3 and 10.5. The result is always the same. (See below.) I would appreciate any help. Thank you.
Thank you, Swaroop. I opened a ticket with support.