In MRF fast spiral scanning is done with variable FA/TR using a highly – up to 48-fold – undersampled trajectory. Spatial undersampling artifacts are mitigated by the MRF dictionary-matching process for the resulting quantitative T1/T2 maps. In this study, we demonstrate how undersampling artifacts can bias MRF results and present strategies to minimize them by spiral-interleave reordering adapted to the specific MRF encoding scheme. An experimental procedure is developed to test for a potential spatial bias in a specific spiral and MRF encoding scheme. The sources of spatial variances are mitigated with appropriate distribution of undersampling artifacts over the temporal MRF encoding.