Well it seems that the loaded excel file had an custom format in the percentage cells, so there it was the problem.
SISilambarasan I Syncfusion Team May 22, 2017 08:45 AM UTC
Thank you for contacting Syncfusion support.
We have checked the reported issue with product version 18.104.22.168 and we are unable to reproduce it in our end. Based on the provided code example, we have prepared a sample to demonstrate this and the same can be downloaded from the following sample link. In that, we have imported the file ‘TestFile.xlsx’(~/Files/) which contain applied percentage formatting in ‘pt-PT’ locale and its loaded properly with applied formats in Spreadsheet. Please find the below screenshot.
Could you please check & replicate your issue in the above sample and send back to us with more information such as custom percentage formatting details or if possible please share dummy excel file to reproduce the issue so that we could able to sort out the cause of this issue and provide you a better solution quickly? The information provided would be great help for us to proceed further.