Understanding Society User Support

Hello. I'd like some advice about weighting variable. I'm using UKHLS waves 1 through 7, individual data.
When I ran svy command in Stata, the number of observations shrink due to zero. I tried iweight but it's not fixed.

svyset psu [pw=my_lw], strata(strata) singleunit(centered)
svyset psu [iw=my_lw], strata(strata) singleunit(centered) // iweight applied for experiment

I am aware that any participant who missed any survey wave, gets zero weight, thus when I copied 2015 weight to the rest of waves, this generated a large proportion of zero weight.
Is there any fix for this, please, and should I? Or should I just report and explain ?
The code below is from user manual.

• my longitudinal weight
  tab wave

/*copy the LAST wave's value over to previous waves
gen my_lw = indinus_lw
bysort pidp (year) : replace my_lw = my_lw[_N]

Thank you and I really appreciate your support.