Dataflow - Failed to analyze issues in the query

Whilst saving a dataflow the error Dataflow - Failed to analyze issues in the query appears and does not let me save or keep my work or anything. The problem seems to be sporadic and related to the size of data (largestg table are below 2.6 M rows).
I dont want to think this is a MS Trick to force us to buy Fabric, as these size of data used to be perfectly managed by standard Pro licensing!!!