ok, so looking at the contract,
{
"token_hash": "74fca4e71f8d3f2bb04cd2c522256716",
"token_address": "0x52ecdbd3faf7ed638d0ad4f90b5435cbfdc41aec",
"token_id": "1",
"block_number_minted": "26121313",
"amount": "100",
"contract_type": "ERC1155",
"name": null,
"symbol": null,
"token_uri": "https://lh3.googleusercontent.com/yoJkJVTLTJsMi0sqkGWCyR2sOgpmhikg4SYQKXcUhAXVvKiHPSeeP4nIldg-oEX9FW_q7Uh8VGa9wlI7zanKTFKu9Fw4Y3D0tdlsfA=w600",
"metadata": null,
"synced_at": "2022-04-28T19:27:16.494Z"
},
This is one of the result, i check the token_uri, it is an image, so a metadata json cannot be created, hence metadata field is null (metadata are in form of json example)
and the it looks like you contract has no name and symbol hence name and symbol been null and it is erc 1155, which is correct
hope this explains some other things, what you experienced earlier was mumbai pos chain been overcrowded its, but it should be ok now