Random values are going weird in conditional statement with seed

from random import seed,random
for i in range(21):
     if i%3==0:
         seed(10)
     if i%2==0:
         random()
     else:
         random()

with above code, result is

0.5714025946899135
0.4288890546751146
0.5780913011344704
0.5714025946899135
0.4288890546751146
0.5780913011344704
0.5714025946899135
0.4288890546751146
0.5780913011344704
0.5714025946899135
0.4288890546751146
0.5780913011344704
0.5714025946899135
0.4288890546751146
0.5780913011344704
0.5714025946899135
0.4288890546751146
0.5780913011344704
0.5714025946899135
0.4288890546751146
0.5780913011344704

which,

a=0.5714025946899135
b=0.4288890546751146
c=0.5780913011344704   

is continuously repeating.

But according to seed(10), i should get only a=0.5714025946899135 with a seed applyed,

and the others should be random.

but why other value (0.4288890546751146 and 0.5780913011344704) is constant too?