It works for me, I'm able to reproduce this issue my side.

if the graphql query used variables in parameters then always expected to send the value of the query variables to be {}. if we pass query variables value to be null then this issue occurs.

Expected Request:

{"query":"query myquery($uri: String = "tcm:5-394-64") \n{ \n
page (cmUri:$uri) {\n id,\n \titemId,\n
\tlastPublishDate,\n title,\n \turl,\n \ttaxonomies{\n
id,key,title\n }\n }\n }\n","variables":{},"operationName":"myquery"}

{"query":"query myquery($uri: String = "tcm:5-394-64") \n{ \n
page (cmUri:$uri) {\n id,\n \titemId,\n
\tlastPublishDate,\n title,\n \turl,\n \ttaxonomies{\n
id,key,title\n }\n }\n }\n","variables":{"uri":"tcm:5-295-64"},"operationName":"myquery"}

I hope it helps.

It works for me, I'm able to reproduce this issue my side.

if the graphql query used variables in parameters then always expected to send the value of the query variables to be {}. if we pass query variables value to be null then this issue occurs.

Expected Request:

{"query":"query myquery($uri: String = "tcm:5-394-64") \n{ \n
page (cmUri:$uri) {\n id,\n \titemId,\n
\tlastPublishDate,\n title,\n \turl,\n \ttaxonomies{\n
id,key,title\n }\n }\n }\n","variables":{},"operationName":"myquery"}

{"query":"query myquery($uri: String = "tcm:5-394-64") \n{ \n
page (cmUri:$uri) {\n id,\n \titemId,\n
\tlastPublishDate,\n title,\n \turl,\n \ttaxonomies{\n
id,key,title\n }\n }\n }\n","variables":{"uri":"tcm:5-295-64"},"operationName":"myquery"}

I hope it helps.

I'm able to reproduce this issue my side.

if the graphql query used variables in parameters then always expected to send the value of the query variables to be {}. if we pass query variables value to be null then this issue occurs.

Expected Request:

{"query":"query myquery($uri: String = "tcm:5-394-64") \n{ \n
page (cmUri:$uri) {\n id,\n \titemId,\n
\tlastPublishDate,\n title,\n \turl,\n \ttaxonomies{\n
id,key,title\n }\n }\n }\n","variables":{},"operationName":"myquery"}

I hope it helps.

It works for me, I'm able to reproduce this issue my side.

if the graphql query used variables in parameters then always expected to send the value of the query variables to be {}. if we pass query variables value to be null then this issue occurs.

Expected Request:

{"query":"query myquery($uri: String = "tcm:5-394-64") \n{ \n
page (cmUri:$uri) {\n id,\n \titemId,\n
\tlastPublishDate,\n title,\n \turl,\n \ttaxonomies{\n
id,key,title\n }\n }\n }\n","variables":{},"operationName":"myquery"}

{"query":"query myquery($uri: String = "tcm:5-394-64") \n{ \n
page (cmUri:$uri) {\n id,\n \titemId,\n
\tlastPublishDate,\n title,\n \turl,\n \ttaxonomies{\n
id,key,title\n }\n }\n }\n","variables":{"uri":"tcm:5-295-64"},"operationName":"myquery"}

I hope it helps.