voice memo truncation, ios

Recently the voice memo app (on Ipad) has been truncating my recordings. The app seems to record a 20 minute note, say, but will play back only a few seconds or minutes. I've uploaded a screen shot from my ipad (Air, 4th gen, 15.3.1). You can see that the length of the recording is supposed to be 23.15 (top left and bottom right), but that only 0:26 seconds are available (playback screen is lighter gray to right of the thin blue line; that's where playback stops). You can also see at the bottom in the small overview display of the recording that playback is finished – the blue line is at the end – and that the end is supposed to be 23:15, but in fact the counter shows that it's 00:26.45. The discrepancy between stated total length and accessible length seems to be a glitch, not user error. The recording should end at its stated total length. Instead it ends early.

Is this just a screen lock problem, i.e. that when screen locks recording stops? Don't think, so, because 26 seconds is not my auto-lock setting; right now it's at 15 minutes. And even if that were so, there shouldn't be a discrepancy between stated and actual total length.