Buds on one plant are so slow to grow

[Durlin]

I have 3 strains in a DWC system Wreckage ,Tutankhamen,and Bubba's Gift. Tut is almost done maybe 2 weeks at best. Wreckage has 2-3 weeks . But the Bubba's Gift is so slow to flower I am beginning to think I may have an issue.Other than the one ridiculously slow plant No other problems.All the leaf looks good no brown or spots. Has anyone grown this strain and is it normal? This is week 6 of flower. The last photo is Tutankhamen,First 3 are bubba's Gift.


6x6 tent
2-400W HPS
Ionic nutes

[Cloud]

I grew some sativa autos a bit ago and they stayed small for 2 months then all of a sudden they were huge. Strain was auto sour diesel haze from seedsman.