if you have a Grid field setup as available to a Fluid Field where the Grid requires exactly one row (ie so the delete row button doesn’t show) and you delete the entire Fluid Field block, the data stays orphaned in the exp_channel_grid_field_xxx table. I'm not certain whether this also happens if there’s more rows in the grid, but I imagine it does. I beleive this is an issue and deleting the Fluid Field should also delete the Grid data.
if you have a Grid field setup as available to a Fluid Field where the Grid requires exactly one row (ie so the delete row button doesn’t show) and you delete the entire Fluid Field block, the data stays orphaned in the
exp_channel_grid_field_xxxtable. I'm not certain whether this also happens if there’s more rows in the grid, but I imagine it does. I beleive this is an issue and deleting the Fluid Field should also delete the Grid data.