CH₂DOH/CH₃OD ratios observed towards low- (yellow), intermediate- (red), and high-mass (blue) star-forming regions: IRAS 16293-2422 (Parise et al. 2002; Jørgensen et al. 2018), IRAS 4A, IRAS 2, IRAS 4B (Parise et al. 2006), SVS13A (Bianchi et al. 2017), CepE-mm (Ratajczak et al. 2011), OMC2-FIR4 (Ratajczak et al. 2011), Orion CR (Neill et al. 2013b), Orion Irc2, W3(H2O), SgrB2(N2) (Belloche et al. 2016), NGC 7538-IRS1 (this work; blue and white stripes), and NGC 6334I (Bøgelund et al. 2018). We note that values derived by Parise et al. (2006) and Ratajczak et al. (2011) were divided by a factor of 2 and 1.5, respectively, due to a spectroscopic issue (see Belloche et al. 2016). The dashed red line shows the statistical factor CH₂ DOH/CH₃OD = 3.