Using Design Suite plugin, user cannot define the product/colorway thumbnail during Images Page creation in FlexPLM

• Using Design Suite plugin, user cannot define the product/colorway thumbnail during Image Page creation
• Clicking Set as Cell Content shows error  "Server Fault detected, Please reach out to administrator" inconsistently in Design Suite UI
• Enabling logger in Design Suite, below logs printed in flexplmwebservice.log

START:          20xx-0x-0x 11:57:20
URL:            https://flexplmhost.com/Windchill/servlet/rest/p76/documents/thumbnail
HTTP CODE:      500
CURL CODE:      0
POST BODY:      {"id":"OR:com.lcs.wc.document.LCSDocument:xxxxxxxxx","thumbnailImage":"xxxxxxxxx.png"}
RESPONSE VALUE: {"errorMessage":"Unable to read temp image"}
END:            20xx-0x-0x 11:57:21

• Below Error is printed in Method Server logs 

ERROR com.plugin76.rest.AbstractRestService wcadmin - Probleminthumbnailsetupfordocument com.plugin76.rest.exception.ServiceException: Unable to read temp image
	at com.plugin76.rest.util.ThumbnailHelper.hasTempPath(ThumbnailHelper.java:94)
	at com.plugin76.rest.util.ThumbnailHelper.storeThumbnailImage(ThumbnailHelper.java:169)
	at com.plugin76.rest.util.ThumbnailHelper.setObjectThumbnail(ThumbnailHelper.java:47)
	at com.plugin76.rest.document.builder.DocumentBuilder.setDocumentThumbnail(DocumentBuilder.java:394)
	at com.plugin76.rest.document.DocumentsRestService.setDocumentThumbnail(DocumentsRestService.java:214)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)