This can happen, and I doubt it's a lighting issue. What I see is progressively smaller leaves. This usually indicates insufficient fertilizer. It's not necessay to binge the plant with high nitrogen, but while the leaves are growing a steady diet of nitrogen is required to keep growths normal. I use a very weak solution (125ppm Nitrogen) but my Phals get this with every watering. I don't change to anything else during the year. Phals right now should be resting or spiking, not growing. They may be finishing leaves or hardening leaves, but new leaves are rare this time of year in Northern Hemisphere (light is too dim). It is common for Phals to reach for more light, even in a south window. As evidence, consider:
where the leaves are growing nearly vertical trying for maximum exposure. I grow mine under full sun. I never turn the plants from their accustomed position.