Issue with bigint unsigned auto-increment field

CREATE TABLE t5(c1 BIGINT UNSIGNED NOT NULL AUTO_INCREMENT, c2 BIGINT SIGNED NULL, c3 BIGINT SIGNED NOT NULL, c4 TINYINT, c5 SMALLINT, c6 MEDIUMINT, c7 INT, c8 INTEGER, PRIMARY KEY(c1,c2), UNIQUE INDEX(c3)) engine=pbxt;

--insert some rows
INSERT INTO t5 VALUES(0,-9223372036854775808,1,2,3,4,5,5),(255,-2147483648,6,7,8,9,10,10),(65535,-8388608,11,12,13,14,15,15),(16777215,-32768,16,17,18,19,20,20),(4294967295,-128,21,22,23,24,25,25),(18446744073709551615,9223372036854775807,26,27,28,29,30,30);

INSERT INTO t5(c2,c3) VALUES(33,34) /* tries to increment out of range */;

Other engines (MyISAM, Innodb, Maria):
ERROR HY000: Failed to read auto-increment value from storage engine
while trying to increment value 18446744073709551615.
SELECT * FROM t5;

c1 c2 c3 c4 c5 c6 c7 c8

101 -102 -103 -104 105 106 107 108

102 0 0 37 38 39 40 41

108 -109 -110 111 112 113 114 115

109 -32 -32 33 34 35 36 37

110 0 -104 2 NULL NULL NULL NULL

111 0 -17 18 19 20 21 22

112 -1 -1 8 9 10 11 12

113 -101 -102 104 105 106 107 108

114 -108 -109 111 112 113 114 115

115 -115 -116 118 119 120 121 122

116 -122 -123 125 126 127 128 128

117 -9223372036854775808 1 2 3 4 5 5

16777215 -32768 16 17 18 19 20 20

18446744073709551615 9223372036854775807 26 27 28 29 30 30

255 -2147483648 6 7 8 9 10 10

4294967295 -128 21 22 23 24 25 25

65535 -8388608 11 12 13 14 15 15

PBXT:
---------------
doesn't give
ERROR HY000: Failed to read auto-increment value from storage engine
SELECT * FROM t5;

c1 c2 c3 c4 c5 c6 c7 c8

101 -102 -103 -104 105 106 107 108

102 0 0 37 38 39 40 41

108 -109 -110 111 112 113 114 115

109 -32 -32 33 34 35 36 37

110 0 -104 2 NULL NULL NULL NULL

111 0 -17 18 19 20 21 22

112 -1 -1 8 9 10 11 12

113 -101 -102 104 105 106 107 108

114 -108 -109 111 112 113 114 115

115 -115 -116 118 119 120 121 122

116 -122 -123 125 126 127 128 128

118 -9223372036854775808 1 2 3 4 5 5

16777215 -32768 16 17 18 19 20 20

18446744073709551615 9223372036854775807 26 27 28 29 30 30

255 -2147483648 6 7 8 9 10 10

4294967295 -128 21 22 23 24 25 25

4294967296 33 34 NULL NULL NULL NULL NULL

65535 -8388608 11 12 13 14 15 15

increments 4294967295.