Failures in CB transaction operations with gocb

CB v6.6
gocb v2.5.1

Transactional Inserts work fie but deletes/replace fail with below error:

transaction operation failed | unknown xattr macro | {\"status_code\":208,\"document_key\":\"6261445628862305918\",\"bucket\":\"test\",\"scope\":\"_default\",\"collection\":\"_default\",\"error_name\":\"SUBDOC_XATTR_UNKNOWN_MACRO\",\"error_description\":\"Subdoc: The server don't know about the specified macro\",\"opaque\":29,\"last_dispatched_to\":\"\",\"last_dispatched_from\":\"\",\"last_connection_id\":\"c85e9106efd1e39d/6e60ad824e08e5dd\"}\n"}

To give flavor of code

gr, err := tCtx.Get(, id)
if err != nil {
	logger.Logger.Debugf(ctx, "cb:tx_delete_docs:cb_error:id:%s:error:%+v", id, err)
                     return err									
err = tCtx.Remove(gr)

Transactions are not supported in CB 6.x

I found that by searching for : unknown xattr macro transactions