When the leaves were budding, some branches on my wine and roses weigela have gold leaves at tips. All other leaves are green. The stems are blooming. Never had gold leaves since planting 5 years ago. Didn't want to trim stems, unless they are dying.
Certified GKH Gardening Expert
It is likely in need of fertilization if you do not do this every year. It wouldn't hurt to go ahead and apply dolomitic lime and wettable sulfur to the area, as this will kill any possible infection as well as condition the soil back to a fertile pH.
This article will give you more information on the care of these: https://www.gardeningknowhow.com/ornamental/shrubs/weigela/growing-weigela.htm