Tagata at Gb5-6 marks glyph number 360, we know, and it divides 180 counted beyond takaure into 68 + 112:

If there is a 'mirror' at puo in Gb8-30, then we can expect another important mark of change in position 112 + 1 on side a:

	111		67
Gb8-30 (1)		Ga5-2 (113)		Ga7-11 (181)
112		68
180

Henua at Ga5-2 is the central glyph of the 16th period, where a new glyph line is beginning:

In the following Ga5-3 the sign of henua is open at its top end, a feature shared with only one other such glyph:

Possibly the reason is to reduce the number of 'real' periods from 31 to 29. In the parallel K text there are only 29 periods, and without a fully drawn border line the sign illustrates a 'ghost', only a fictional character.