crypto/elliptic: attempted operation on invalid point

I'm using the r and s value after signing a payload to then decode it back to a signature.
First I convert the string values to a bigInt with

myBigInt := new(big.Int)
myBigInt.SetString(byteValue, 16)

Then I convert to the signature with

elliptic.Marshal(elliptic.P256(), &myBigIntR, &myBigIntS)

When I do this locally, I have no issues whatsoever. I am pushing this then to github and render.com picks it up. However on the server, i get:

I Receive:

Mar 15 05:36:31 PM  2023/03/15 17:36:31 http: panic serving : crypto/elliptic: attempted operation on invalid point
Mar 15 05:36:31 PM  goroutine 1252 [running]:
Mar 15 05:36:31 PM  net/http.(*conn).serve.func1()
Mar 15 05:36:31 PM      /usr/local/go/src/net/http/server.go:1854 +0xbf
Mar 15 05:36:31 PM  panic({0xc5ff40, 0xfaae70})
Mar 15 05:36:31 PM      /usr/local/go/src/runtime/panic.go:890 +0x263
Mar 15 05:36:31 PM  crypto/elliptic.panicIfNotOnCurve({0xfbc088?, 0x15d3950?}, 0x40?, 0xc000100400?)
Mar 15 05:36:31 PM      /usr/local/go/src/crypto/elliptic/elliptic.go:215 +0xa5
Mar 15 05:36:31 PM  crypto/elliptic.Marshal({0xfbc088, 0x15d3950}, 0x15d3950?, 0xc0002c2020?)
Mar 15 05:36:31 PM      /usr/local/go/src/crypto/elliptic/elliptic.go:105 +0x31

I cannot work out what could be different between the server version and a local version.
Has anyone come across this. Google didn't have much in the way of an obvious issue I could be making.

Using the sigR and sigS values:

	v2signature := new(refs.Signature)
	v2signature.SetScheme(refs.ECDSA_SHA512)

	signatureData := elliptic.Marshal(elliptic.P256(), &sigR, &sigS)
	v2signature.SetSign(signatureData)
	v2signature.SetKey(containerOwnerKey.Bytes()) //1. this should be the container owner

	var bearerV2 acl.BearerToken
 	bearerToken.WriteToV2(&bearerV2)
	bearerV2.SetSignature(v2signature)

This is from an SDK that uses bearer tokens to access assets on a remote server.
I am creating a new signature using the two values r and s, with scheme ECDSA_SHA512 and then attaching that to the bearer token

I ended up sticking the whole lot in a docker image so that I could control versions of everything locally and remotely. This solved my issues. I suspect the cloud service was using some different Go version or something. Thanks for those who helped out!