Unfortunately issue can’t be reconstructed locally.
Mentioned error line related to code which used for row rendering and it works correctly in case of Crome in local samples.
If issue still occurs for you - please provide any kind of sample where problem can be reconstructed ( you can send such info directly to support@dhtmlx.com )
Also, latest version of dhtmlxgrid with all fixes up to date was sent by email, please try to use it instead of original one.
Which version of Google Chrome you are using?